In response to a request by Melissa ( I did promise her I would ask people I deal with and put this information out and I never break a promise to a lady) and for anyone with general interest in the techniques, I'm putting up this thread. I've contacted a few people for their input ( not all have answered yet) so what I post here isnt just my experience ( some of this is well outside my personal realm of expertise but I have over 30 years of networking and contacts- I can usually get an answer), but a compilation of techniques, experience, lessons learned and what is considered "strong evidence" ( based on a scientific and legal view as well)

I'm going to focus on what she asked specifically but I'll attempt to find out anything anyone wants to know.

Enjoy

Forensics supplies ( This is not an endorsement of any company or product)

These are just 2 I have used over the years and if anyone has a business and opens a business account, they have good discounts.

www.spexforensics.com

www.evidentcrimescene.com

I use spex almost exclusively ( personal preference)

Collecting Biological samples for potential DNA extraction

( Hat tip to my lab and their taking time to answer a lengthy question filled email without charging me and to an FBI guy I hunt with)

1) Cleanliness is next to Godliness regarding DNA- current methods are so sensitive that touching and even breathing on a potential sample ( that surprised me about the breathing) can contaminate a sample- use a mask, gloves and net while gathering the sample)

2) ALL specimen bags, tools etc should be ONLY ( the bags and tools such as tweezers) ones recommended for lab use and be single use and sealed until needed. Various plastic containers, tools etc are made a variety of ways and some of the platings, polymers etc will react with the sample. ( dont use just your regular sandwich bags or clean 5 gallon bucket) The equipment must be completely sterile and non reactive. ( theres an ISO and NIST standard for most of these)

3) ALL hand tools ( pliers, snips, whatever) should be bleach washed, completely degreased and boiled ( or steamed) sterile, lightly dusted with talc ( for anti rust) and sealed in a bag such as from a food vacuum sealer. You may have to cut or otherwise remove a portion of whatever the sample is on for testing and anything such as oil or whatever on a tool will likely destroy a sample if it comes in contact with it. It is PREFERRED to NOT attempt to scrape or otherwise attempt to remove a sample but when it must be done- make every attempt to "cup" liberally underneath the sample rather than trying to scrape it off of the surface.

4) Reagents- test the suspected sample with a reagent to ensure its a biological before gathering ( there are kits for this)

5) Dry samples- it is STRONGLY recommended to NOT make any attempt to rehydrate a sample in the field. ( the preferred method is to remove the artifact and let the lab do it) but if its a must, use ONLY sterile water designed for this purpose from a sealed ampoule. ( blood and other media tend to separate when being absorbed and improper hydration can damage a sample)

5) Packing samples for shipment- the preferred method of sample preservation for shipping- is to air dry them with a blower ( or hair dryer, commercial dehydrator on LOW heat- you want the air flow to wick away moisture, not too much heat) as moisture in the bag may not be sterile and may attack the sample.

6) million to 1 shot here ( the agent told me this has been done- but its a shot in the dark)- in the event theres a print that could possible have skin residue or anything else- get the filter ( from the supply house) and use a clean/sterile vacuum ( cleaned as described above) and lightly vacuum the print paying attention to the heel and toe areas ( most likely points) and send the filter and contents off .

more later- still waiting on other answers to questions

Just curious- is this along the lines of what people seemed to want?

It seems pretty thorough to me, longtabber. Thanks for taking the time to post it.

Sorry, I was going to chime in here earlier. Thanks for taking the time to start this thread and for collecting a few things to get this started.

From personal experience in DNA work, it seems pretty thorough. Oddly enough breathing and hair cause more contamination than you'd expect.

good information! I can say it's what I want, and I'm sure others too.

I third the thanks.

>>>From personal experience in DNA work, it seems pretty thorough. Oddly enough breathing and hair cause more contamination than you'd expect.

I wont lie- that one shocked me- I understand hair and stuff from my work, I never would have thought to even consider breath as a contaminant.

Still waiting for more

ETA- Its not like I know everything ( i dont) but a large part of my job is finding out what I dont know from people who do know.

I'm working on several other topics for this ( in response to my promise to melissa) and I'm going to rush them in because I'm warping out of orbit Sunday coming. ( back tu deh Ahlands Mahn so I'll be at the mercy of 3rd world internet service till Christmas)

More DNA tips from those who know a lot more about it than me ( some of these are longshots but luck does count)

1) NEVER put labels and or writing IN the sample container ( bleaches in the paper process and the inks will attack the sample) this is in response to enlightening me that this used to be a taught practice in places.

2) When scanning the area for potential samples ( urine,blood, saliva, semem etc)- a UV light can ( emphasis on can) aid in detection of possible sample

3) should a track with green foliage ( such as leaves) in the base be detected- its POSSIBLE to gain skin cells from the foliage. ( it was explained to me that green [ as opposed to dry] have a tendency to catch cells in their grain structure. Another longshot but potential source. It was also said that pine needles would damage the sample.

4) Any suspected "thrown" objects ( such as these rocks and wood) could have DNA potential ( the coarser the material, the better)

5) a "rock" can be dusted with fine talc and may yield prints ( 2 million to 1 shot)

6) samples exposed to direct sunlight or extreme moisture or more than 30 days old ( applying to samples outside in the woods) are probably not worth collecting

7) Always check foliage within 3 feet ( either side and ABOVE) of a suspected path up to suspected shoulder level ( more from my side of investigating as this is where evidence of snagged clothing can often be found from foliage whipping)- you never know what snagged skin, hair or made a cut. ( 1000 to 1 shot)

CASTING do's and donts ( this is a combination of standard LE and industrial methods for making castings that actually contain evidence)

1) the print itself- the first question is to answer WHY am i casting this print and what do i hope to determine as a result. ( theres more than one technique for discovery of different things- casting is not a "one size fits all" science)

A- the print itself- unless you want a representation of a hole in the ground- if a print doesnt have characteristics to evaluate, theres no need to cast it. A good visual examination is the first thing to do. "What makes this print worth casting" is the perspective to look from. If you ever hope to gain anything other than a print of a hole, dont cast prints in snow or any with standing moisture or saturated substrate.

2) the Tool Kit

hair dryer ( preferably a heat gun)- if theres no power source, dont worry about it- the ideal print is cast from a dry surface but that aint always possible.

you MUST have commercial "dust and dirt" hardner and "snow wax" ( these act as a base and keep a lot of dirt from being pulled in with the casting- you want a cast of the impression, NOT the first layer of dirt)

Talc or flourescent powders ( they highlight minor details, act as both a dessicant and a release agent)

The finest ( particulate size) casting agent you can afford

chicken wire,hardware cloth, coat hangers etc ( making a frame for thin and fragile castings)

Spreader tips

3) things to be aware of:

Dessication- drying of area

Hydration seepage- pulling of substrate moisture forming a barrier, watering down the casting agent, or washing away detail

Capillary action- this is where air gets trapped along the jagged edges of a substrate ( the edges of dirt) and doesnt allow the casting agent to fulld enter the detail and this air "moves' due to the weight and motion of the casting agent making all kinds of "squigglies"

a DIGITAL microscope ( 200X or better) ( about $150)

4) Technique

mix agent to death ( mechanical mixer with battery drill works best) then agitate it ( vibrate it) to remove as much entrained air as possible and keep that up till time to pour

1) take several pictures with the microscope PRIOR to doing anything ( put stick in ground- subsequent pictures need to be from the same location, distance and angle)

2) spray dirt hardner ( when dry take second set of pics)

3) apply powders ( best with a puffer but can use a sprayer or VERY soft,fine brush) ( take 3rd set of pics)

4) pour- there are several accepted techniques but the general idea is a gentle pour preferably from a wide trough covering the entire area with a THIN coat before filling.

5) Insert frame ( especially for thin castings)

REMOVING

The accepted way is to gently remove substrate from around and under as much as possible ( best way is with an air tank) and "roll" out starting with the thinnest part. ( that may sound backwards but you want the least pressure on the thinnest part)

What you can expect.

You will have several reference pictures so you can attempt to determine the ratio of print detail versus casting effect. ( many things will show up in the pictures the cast may not get)

your cast should be reasonably clean of substrate and require much less mechanical cleaning to see detail ( plus if you got lucky, the powder held the detail)

This ought to help people get started- there are more advanced methods and different techniques

...but UV light (at the "right" wavelengths) is also used for decontamination because it can "destroy" DNA, so this might not be the best idea with certain samples even (though it usually takes extended exposure)....

Thats correct- I should have been more specific, I stand corrected

For this purpose one must use nothing but a long wave UVA type "blacklight" in the 350-400 nm range

Unless your mixing a large quantity - even US Gypsum would disagree with you on this. Mixing with a latex gloved hand is the best option for what we are doing. The same instructions I was given by them, are the same instructions given to the FBI - by US Gypsum.

Otherwise, your mixing in too much air - and you can only remove so much trapped air before the casting agent sets, and then you have a mess.

Debate this all you want - but I plan to cast as accurately as possible.

I also see no mention of the fact that the casting agent needs to be added to the water - not the water to the casting agent. This is very important and should not be ignored.

What your using for reinforcement also have issues. I use aluminium fence ties, as taught to me by 2 of the finest casters I know. Chicken wire will degrade inside the cast, along with the other items you mentioned. Then you have no reinforcement

This is great! Thanks for taking the time to do this. Although I know alot of this stuff, alot of it I don't (much we naturally forget as well).
Thanks again LT and now the Apeman coming in with the assist too!

I am aware of what is taught and what I'm telling you is the best way. The field instructions are designed for general usage. Its not a matter of right and wrong, but good, better and best.

Proper mechanical mixing is the gold standard everywhere as is agitation for settling. Ask anyone in the cement or aggregate industry. ( which International Gypsum, Portland and others who make up the consortium write the books for and are some of my customer base)

The reason they tell you about hand mixing is because most people dont know how to mechanically mix properly so they screw it up. They slop it around like a milkshake. Yet go to any plant anywhere- see what the "pros" do.




>>>I also see no mention of the fact that the casting agent needs to be added to the water - not the water to the casting agent. This is very important and should not be ignored.

No, I didnt intend to write a short novel- i left some of it to people to actually read the instructions

>>>What your using for reinforcement also have issues. I use aluminium fence ties, as taught to me by 2 of the finest casters I know. Chicken wire will degrade inside the cast, along with the other items you mentioned. Then you have no reinforcement

After 50 odd years- is that really that important?

And, I am saying based on the months (actually over a year) of work and testing I have done - your way is not the best way for people who do what we do. Attention must be paid to certain details of this process. And, yes - even after 50 years I want those casts that are deemed good enough to stand up to scrutany - to last another 50 years if possible.

How do you know it's the best way? Is this the method you use?

Good question.

From the USG website:

As someone who had to suffer through a poorly mixed homemade icing the other night I can attest to the importance of thorough mixing. If I'm doing a two stage casting I beat the first stage like it owes me money.

When it comes to reinforcement just remember... nothing organic and nothing that will rust.

I'd also add that all pertinent information be recorded on the back (top side) of the cast via engraving before the cast comes out of the ground.

By the way, thanks for all the info longtabber.

What part of its industries "gold standard' did you miss?

Working for a month or a year doesnt mean anything was ever done "right" or the "best' way to begin with

the people who 'do what we do" have a history replete with "less than acceptable" results and other "people' who do what you do at a MUCH HIGHER LEVEL were trying to help you- but once again, narrow minded arrogance gets in the way of best practices.

If you want a cast that will stand up to 'scrutiny"- then throw away everything you have now and think you know and START OVER because what you have now isnt "nothing" its LESS than NOTHING

If you want something to last forever and last 50 plus years- dont worry about the internal frame ( it just adds strength)- you better come up with a different casting media- if you want a super skeleton- forget aluminum- you need titanium

What part of how do you know did you miss? You stated above that it's a mixture of LE and industrial methods...who mixed the methods? You? Someone else? Has it been tested?

http://www.gypsumsolutions.com/webQA/webQA...ng/Mixing#prob1

Yes, that is in essence exactly what I said - right up until the mixing. How many researchers in the field carry with them a high-speed, direct drive propeller mixer - hell, how about just the juice to run it in the field??

Which is exactly why hand mixing in this situation is the best alternative. Using anything smaller than a paddle or your hand will create too many air bubbles - and give you artifacts.

I mixed the methods ( and i was referring to the techniques rather than the actual chemistry)

Yes, its been tested, millions of times for over a century. The standards are global.

I "know" because i deal with castings and aggregates all the time( and i'm stamped to approve and test them) ( thats a large part of what NDT is)

I'm glad i was warned about this.

This is what happens when ego meets reality

Here are some factoids for you and Melissa

1) mixing an aggregate is paramount for uniform consistency, strength and quality

2) mechanical mixing is the UNIVERSAL accepted "best practice"

3) mechanical agitation is the UNIVERSAL recommended method for removing entrained air

It makes no difference whether you are casting a print or pouring a building- the laws applying to aggregates dont change ( polymers are a wee bit different but not much)

I hope this helped you out.

An excellent and detailed article on the methodology on finding and casting suspected bigfoot prints was written by Rick Noll in 2001. It can be found here. It is the method I use in the field because it's practical.

Its not hard to carry a BATTERY DRILL with a mixing blade ( the battery has the "juice' in it)- again i offered the BEST method- not the method the technically challenged are stuck with

Hand "mixing' isnt the "best" of anything- if you believe that, "hand mix' your next cake

I respectfully recommend you dont critique things you have zero understanding of

There is no ego about it, except yours. I just asked you a simple question and you chose to answer it with attitude. I didn't say a thing about aggregate or mixing method...you stated the method was a mixture of methods between LE and industrial and I was curious who mixed the methods. Chill out...

OK, i was aggrevated by someone else- not you

I stand corrected and offer you my fullest and sincerest apology. i was wrong in my post to you.




When did Rick Noll become an expert? What are his credentials?

more importantly, what are his RESULTS?

And people wonder why we are beat up and called unprofessional.

This is why. You are using outdated information - I say outdated, because people stopped using chicken wire in casting material a very long time ago for this, hell Im shocked you didnt recommend the use of a popcicle stick.

I think it is you who does not know what your talking about. As my methods have proven results, and I have only seen artifacts when I deviate from the methods I discussed in this thread.

Apology accepted.

Trust me when I say all anyone wants is the best methods to collect the best evidence possible.

Rick Noll can provide more info, but I believe he works in aerospace engineering and with casts and casting materials daily.

>>Apology accepted
Thank you

>>>Rick Noll can provide more info, but I believe he works in aerospace engineering and with casts and casting materials daily.

I have customers such as NASA, Gulfstream and a few others ( ga Gulfstream)- they dont do much casting as everything they do has to be machined so I'm curious as to where casting is applicable to his career field or his expertise is related to it.

But, I suppose i need to talk to him. it wont take but a few questions to see.

>>And people wonder why we are beat up and called unprofessional.

no "people' dont

>>>This is why. You are using outdated information - I say outdated, because people stopped using chicken wire in casting material a very long time ago for this, hell Im shocked you didnt recommend the use of a popcicle stick.

you are arguing nothing ( other than for the sake of arguing) because heres reality- no support membrane is going to "rust" unless either chemicals or oxygen attack it ( thus the term oxidation) and casting compounds are mostly inert ( as compaired to cements) There are structure here and now that have held up for CENTURIES with the described methods.

CW is cold galvanized and resistant as well as suitable for the application- you are arguing 'longevity" as if it means something ( it doesnt)

>>I think it is you who does not know what your talking about. As my methods have proven results, and I have only seen artifacts when I deviate from the methods I discussed in this thread.

First of all, you dont have the knowledge or experience to even voice an educated opinion here- you are just parroting word from others and you are letting your ego prompt your speech.

You dont even know what an "artifact" is- much less how to avoid one ( thus the initial thread and the prep work)

"your" methods have produced cast replications of a hole in the ground and nothing else

I'd actually like to see something to support this.


I take it you have yet to use that pumice you purchased.

This one is particularly interesting to me for reasons I'd rather not get into at the moment. Is 30 days the cut off for objects sheltered from the weather, and if so what would be the estimated cut off for objects exposed to light and moisture?




I was going to ask about entrapped air causing casts to break during altitude changes during shipping, but in hindsight if the cast is prepped and poured correctly it would seem that wouldn't be an issue.

So, apparently the FBI is using substandard methods as well. They forgot their electric mixer....

Regardless of the Casting Agent - the mixing procedures remain the same.

>>This one is particularly interesting to me for reasons I'd rather not get into at the moment. Is 30 days the cut off for objects sheltered from the weather, and if so what would be the estimated cut off for objects exposed to light and moisture?

I specifically asked the question ( as you posed) and the 'correct' answer is that there is no answer ( too many variables and possibilities)- her answer to me was a "rule of thumb" ( based on her experience and publications)- the bottom line, if you have a sample- test it and see, but after the effects of weathering, dont be overly hopeful about positive results.

>>>I was going to ask about entrapped air causing casts to break during altitude changes during shipping, but in hindsight if the cast is prepped and poured correctly it would seem that wouldn't be an issue.

its literally impossible to remove all entrained air from any aggregate, pouring ( unless you slop it) doesnt entrain air- you mixe it good and agitage it good- you will be fine

That's what I was thinking. I imagine I would still err on the side of caution and use ground shipping.

In your experience, or in consulting with others, is there anything you would add regarding a splash or dual stage casting?

What's your source on this?

Click the link and find out.

FBI.gov - its right in the post wolftrax.

In case you missed it.

http://www.fbi.gov/hq/lab/handbook/intro14.htm#casting

Oh, and apparently your not familiar with the joy of the ziplock bag. They keep air out.

Im done with this. Enough bad information has been given out on this topic.

Once again, you let your ego and arrogance get in the way of the subject matter

there is the "book" ( which has been updated) and what works BEST ( remember FIELD methods may in fact be impromptu)

BTW- WHO do you think told the FBI the way? ( the people who make it)

can you not understand the very simple difference between the "textbook" method and more 'advanced" methods ( as i was describing?)

What kind of point are you trying to prove? YOU asked for help. YOU are the one who has actually produced NOTHING, YOU are the one who wants to better things.

Nothing I have put here is less than Industry standard and factually correct, yet you STILL whine and try to sharpshoot ( which was ineffective but entertaining)

Why is that? Are you seeking some form of absolution that makes all your substandard and ineffective methods OK? Are you trying to make mediocre into state of the art?, Are you trying to make excuses for failed attempts so egos and agendas can be salvaged?

Or is it simply a bruised ego from arguing such things as the lagality of defense of property, use of screwboards, repo people and a 'right' to shoot trespassers in Texas and having been proven wrong in all of the above?

its obvious you have no techincal knowledge about the subject and are just parroting words- so why are you arguing with those who know what they are talking about? Wasnt it you days ago WANTING to know WHY things "failed" and was asking for answers? You GOT answers ( which are correct) and now you whine more- whats up with that?

If you "knew'all the answers, you wouldnt be doing so much WRONG ( or less than the best methods available)

From the prefect world scenario

in the prefect world- you would want a thin layer of media from bulb or aspirator or spreaders to cover any important features- THEN pour ( this is what you are describing as stages- stage 1 is for detail, stage 2 is for strength)

Universally, 'splash" is the WORST thing to do ( when you want detail)

the only "rule of thumb" is this

there is air in both the substrate as well as being captured between the substrate and the pour- do everything you can to minimize that ( spread in place for detail) then a GENTLE pour

This thread has the opportunity to be a great Q&A session with someone who, like him or lump him, obviously has good pertinent information to share. Perhaps instead of having a contest to see who has the highest high horse we should instead be trying to have a meaningful discussion that might actually further us along (which is something everyone claims to want).

Thats good you are done with this- now we can get back to sharing valuable and useful information- you were quite a distraction.

I hope you will learn something- even if by accident

Uhhhh, yeah, I'm not seeing anything in that link about using anything smaller than a paddle to mix your plaster causing artifacts. It's not saying to use your hand either. I guess you still haven't used pumice. Anyways, good to see the bad information won't be given out anymore.

Not to say that you're getting over my head but... whoa. "Bulb"? "Aspirator"? What exactly would these be and how would I fit them in my field pack?

This is surreal.

QUOTE( Melissa)
"Using anything smaller than a paddle or your hand will create too many air bubbles - and give you artifacts."

QUOTE( wolftrax)
"What's your source on this?"

QUOTE (Melissa)
"Click the link and find out.

FBI.gov - its right in the post wolftrax.

In case you missed it.

http://www.fbi.gov/hq/lab/handbook/intro14.htm#casting

Oh, and apparently your not familiar with the joy of the ziplock bag. They keep air out.

Im done with this. Enough bad information has been given out on this topic."

***

I'm at the link, I'm missing it, it's not mentioning "paddles" and "hands" (but rather "sticks" and "fingers"), it's not mentioning these "stirrers" as the first stir choice, and so on. I am missing something, but I think I've got your link correct? As of 6 months ago I was caught up with those who cast and their detailed "methodology" reports ... but I never read anything about anyone using colored dental stone, plastic bags for mixing (and Ziplocks<r> only keep out air if the caster or kid packaging his sandwich gets the air out in the first place), and pouring casting material into water. So are the techniques below the ones you're using from A to Z, Melissa? If not, it would be great clarifying information on which techniques you use, the source of each technique, and how your expertise has led to the combo you've come up with. Thanks ... Dana.

***

http://www.fbi.gov/hq/lab/handbook/intro14.htm#casting
Casting Three-Dimensional Impressions
Casting a three-dimensional impression in soil, sand, or snow is necessary to capture detail for examination. Dental stone, with a compressive strength of 8,000 psi or greater, must be used for casting all impressions. The compressive strength is listed on the container along with the proper ratio of powder to water used for mixing. Dental stone is available through local dental supply houses. Colored dental stone is preferred.

Plaster of Paris, modeling plasters, and dental plasters are not sufficiently hard, do not resist abrasion when cleaned, and must not be used.

Mixing Dental Stone in a Bag
Store dental stone in resealable plastic bags. An 8-by-12-inch resealable plastic bag can store two pounds of dental stone powder. With premeasured bags, casting impressions at the crime scene involves only adding water. The bag containing the dental stone powder can be used to mix and pour the dental stone.

To make a cast, add the appropriate amount of water to the bag and close the top. Mix the casting material by vigorously massaging it for 3-5 minutes through the bag. Ensure that the material in the corners of the bag is also mixed. After mixing, the material should have the consistency of pancake batter or heavy cream.

Mixing Dental Stone in a Bucket or Bowl
If the impressions are numerous or large, it may be necessary to mix larger quantities of dental stone in a bucket or bowl. The dental stone should be slowly added to the water and continuously stirred for 3-5 minutes. After mixing, the material should have the consistency of pancake batter or heavy cream.

Pouring Dental Stone
Casting material has sufficient weight and volume to erode and destroy detail if it is poured directly on top of the impression. The casting material should be poured on the ground next to the impression, allowing it to flow into the impression. The impression should be filled with casting material until it has overflowed.

If the mixture is too viscous to flow into the impression, vibrate a finger or a small stick on the surface to cause the dental stone to flow into the impression. Do not put the stick or finger more than 1/4 inch below the surface of the casting material because it can damage the impression.

Before the cast completely hardens, write the date, collector's initials, and other identifying information onto it. The cast should be left undisturbed for at least 20-30 minutes in warm weather. In cold weather, the cast should be left undisturbed longer. Casts have been destroyed or damaged when lifted too soon. If the cast is in sand or loose soil, it should lift easily. Casts in mud or clay may require careful treatment and excavation when being removed.

Allow the cast to air-dry for at least 48 hours. Package the cast in paper, not in plastic. A Laboratory examiner must clean the cast.

a "bulb" is what "looks like' a baster (squeeze bulb with a nozzle) and it "spits"

Aspirator is similar but looks like a spray bottle


The idea is to place the contact layer GENTLY ( from top to bottom) rather than lateral movement ( which could distort detail)

in any casting- the ONLY thing you are after is the surface detail- anything else is support

So, and just to make sure that I've got this right.

After thorough mixing of the material and prepping the track, a person would...

A - Fill the bulb with material

B - Apply by vertical "spits" instead of lateral pours (or spray via an aspirator*).

C - Establish a base coat covering all the surface detail using the "spit" method.

D - Pour a backing mold.

Correct?


* - Do you know of any small, compact aspirators that would be easily included in a pack?