Bondo

[flinter49]

Need to make a pattern and was wondering if vaseline would work for a release agent for bondo? I need to form a portion of barrel in a wood pattern. Any and all advise is greatly appreciated.

[Dave B]

vasline is what Dave Rase used to lub up his barrels for making his bondo pattern for inletting the stock blanks for the barrel with his carver

[Scota4570]

Lots of stuff will work well.  They make actual mold release for fiberglass.  It is not greasy-messy.

The biggest issue I have is locks, places in the part being glass bedded that mechanically catch the part from removed later.  Fill those with wax or clay. 

Paste wax is an excellent release agent.  I slather it on and melt it with a heat gun.  I keep lanolin in the shop.  Works great too.  Lanolin mixed with alcohol is an great rust preventer and high strength lube.  Once the alcohol is gone the amount of lanolin is tiny but even.   

[Jakob]

I normally use a light coat of wax and then this for any kind of molds:
https://fibertek.ca/collections/sealing-release-agents/products/pva-poly-vinyl-alcohol-release

It's super easy to apply and washes off easily with hot water and soap.

[flinter49]

Thank you everybody for your help. I certainly appreciate it.

[Dave B]

i tried to use turtle wax on a longrifle bedding and portions of the bedding stuck to the barrel with a coating of the wax. it was a nightmare getting the barrel out. I had to heat the bejesus out of the barrel and several sections of bedding ripped out still sticking to the barrel. Never again.

[Daryl]

I've never used bondo, but have used various commercial bedding compounds and several epoxies as well for bedding. Acraglas gel, Brownell's brown bedding and the epoxies all released well
when using red synthetic axel grease for the release agent. When pressed into the bedding, it goes exceptionally thin on the steel and ALL engraving, marks, scars and tattoos are left in the compound upon release of the barrel.
I've been using the same 'tube' of axel grease for about 30 years & probably over a dozen "jobs", mine and other people's.

[john bohan]

I like Kiwi shoe polish,works well with JBweld and any other epoxy I've used.

[sdilts]

I've been using Pam spray cooking oil, well actually the dollar store version, as a release for AcraGlas. I've had good luck with it.

[577SXS]

I use Treewax floorwax for a release agent. Most good paste floor waxes will work. I've used Treewax for over 40 years and never stuck a part. I've bedded a hundred plus of bolt actions. I would not use bondo for any wood or gun repair. I use JB Kwik for most of my bedding now. Use a good epoxy for wood repairs or a high strength wood glue and an inletted piece of the same wood you need to repair. Make sure the wood grain in the repair is running the same direction as the piece you are using to fill the repair. If the grain isn't running the same direction it with stick out like a sore thumb.

[whetrock]

Thanks for the warning about not using Bondo in repairs. In this situation, I think the original poster was just using Bondo for making a pattern for precarving a stock. Bondo seems to work fine for that. The actual barrel to be used (or one exactly like it) is laid in a mold box filled with bondo. Once removed, the resulting impression can be used as the guide/mold for the stylus on the stock duplicating machine. (Maybe that was clear already?)

When you are using the JB Kwik in bedding, do you color it any any way? Does it come out grey color like the older JB weld products? Do you try to work glass fiber into it, comparable to Acraglass? Or maybe that's not necessary?

[Daryl]

Two different types of JB, for wood and metal "filled"?
I used to use Devcon Plastic Steel when it was a 50/50- mix. It was marvelous for bedding jobs, super strong and zero shrinkage.
They have a new Devcon with different mix ratio, bought some, but haven't used it.

[whetrock]

So, for a mold making, would the JB products a good choice? I think people use Bondo for barrels simply because it is large volume, sets quickly, and is relatively cheap per unit of volume. But other products might be good if the mold box were made more carefully, so as to minimize void space that had to be filled.

[Jakob]

Plaster is your most basic mold material and highly versatile. It really depends on what you are going to use it for.

[David Rase]

I use Johnsons Paste wax for my release agent when making a Bondo pattern.  Been using it for 25+ years.
R/David

[B.Habermehl]

Fred Miller used bear grease forever. As a release agent. BJH