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Using Marine Tex

9K views 4 replies 4 participants last post by  adrbe 
#1 ·
A question came up about what type of epoxy bedding is best to use for G.I. fiberglass stocks. I still use LOTS of Accraglass for restoring worn out Garand stocks, but I think for this application, it is not the best or even a really good choice. I would suggest Marine Tex as that stuff was MADE to stick to many different kinds of fiberglass in the Marine/Boat repair Industry. I know I only use Marine Tex to "glass" most G.I. fiberglass stocks. Marine Tex is an EXCELLENT general purpose bedding to use for wood stocks as well.

That question inspired me to write a thread on Marine Tex I can refer back to later.

I first began using this stuff when my brother brought home a couple of kits from Mullins Machine Corporation in the early 80's. They tested every fiberglass kit or material on the market and this was the best stuff to withstand shock and wear for the "fingers" that hold the filter and tobacco part of a cigarette together when a machine shoots a bit of glue to glue them together. That might not sound like a big deal, but when this step is done at the rate of tens of thousands of such parts glued together per minute, one can see it was a big deal. Well, Mullins spent a lot of money having all the fiberglass materials tested at that time INCLUDING everything on the market and Marine Tex came out on top by a wide margin. This stuff is still rated very well today in repairing fiberglass boats. So I took the kits into the RTE shop and started working with it. I quickly came to love this stuff and gave a couple kits to the Armorers on THE Marine Corps Rifle Team to try. Within just a couple of years, it became the primarly glass bedding material we used because it was/is so good. Even after the Big Team went to a couple other things for skim glassing, we still found this stuff great for the base coat of a glass job.

Before we go any further, there is something everyone MUST know about this stuff. It is EXTREMELY IMPORTANT you measure this stuff by volume in a ratio of 5 parts resin to 1 part catalyst. If this isn't done, the material will come out soft. You DO NOT "eyeball" the quantities to mix as I can almost guarantee you that you will get soft glass that way. Mix it correctly and it is GREAT stuff. Marine Tex will stay good after the resin and catalyst containers are opened for a good four or five years at least. So short shelf time is not a problem. Just tighten the containers up and it will last a long, LONG time.

With some of the kits, you get a little mixing cup to use and it is not bad. However, you can only use it one time. We used the wax coated paper coffee cups and measured them by filling them with water at the quantity we wanted, holding it up to the light and then marking the outside of the cup. Then we dumped the water out, blew it out dry with compressed air, and used the marking on the cup to fill it with resin. Well, that's a PITA to do and it took me a while to figure out something better.

One of the most successful "first efforts" was using a set of cheap/thin set of aluminum kitchen measuring spoons. I used one set for years until I decided to not be quite so stinking cheap and buy a set that was made out of rather thick stainless steel and I have been using them for over 10 years now. However, if you are only going to use the stuff on an occasional basis, the almuminum kitchen spoons will work. There are a few things that are important when using these spoons.

The first is that you only fill the spoons up to the top of the spoon and not overfill it. I use an artist's palette knife to do that and scrape the knife across the top of the spoon after I put the resin or catalyst in the spoon. That gives me a "true" volume measure. You could use a cheap butterknife to do this, but DON'T use your normal table wear as you don't want to ingest anything that might be left over after cleaning the knife. You do need at least one straight edge on the spoon to do this and you can file a straight edge on a cheap butter knife. The reason I use a palette knife or butter knife is the rounded front edge makes it easy to get the material OUT of the spoon measure because the measure is rounded. You don't want to leave any more material in the spoon measure than you have to and you will get enough out with a round edged knife. I tried a cheap 4- 5 dollar palette knife, but the blade was just a bit too thin and flexible. I found it was better to spend about 8 to 9 bucks to buy one with a firmer blade. BTW, the palette knife is also excellent for pressing the mixture into the stock, and especially in tight places, so it serves a good purpose there as well. Here is a link that shows what a palette knife looks like:

http://en.wikipedia.org/wiki/Palette_knife

The second thing about using kitchen spoons is MAKE SURE you clean them after you dig out the resin or catylist with the knife. I use acetone on paper towels to do this and it gets rid of any left over material. I most strongly suggest you clean the spoon this way after you use the resin and BEFORE you put catalyst in the spoon and this to ensure you will get a proper mixing ration. When you are done mixing, clean the spoons this way before you use the mixture and you won't ruin the spoons by allowing the mixture to harden in the spoons.

The other EXTREMELY IMPORTANT THING to know about kitchen spoons is that a Tablespoon is THREE teaspoons and not two teaspoons. I screwed up a couple batches and got soft glass until I figured that out, I have to sheepishly admit.

If you are not familiar with Marine Tex and or don't have a Marine/Boat Supply store in your area, here is a link where you can buy it in various sized kits:

http://www.brownells.com/.aspx/pid=1...uct/MARINE-TEX

OK, now as to colors. I use the grey stuff exclusively. The white color was made to blend into boat hulls. I know some folks use the white and get special pigments made for fiberglass, to try to color it close to wood color. I tried that a couple of times and decided it just wasn't worth the added time and effort. The dark grey color and keeping the bedding material under the receiver makes it almost invisible. BTW, if you try a pigment that is not made for fiberglass, it COULD soften the bedding when it hardens up.

The next thing to discuss is what size kit to buy. I have only used the 2 oz. kits a few times in emergencies when I HAD to get just a little more and had to get a gun done before waiting for a larger kit to come in. Then it was worthwhile to buy this size kit locally. The 2 oz. kit is not enough for a full glass job, though it is enough for a thin skim glass job. If you have solid bedding material in one rifle and all you are going to do is one thin skim glass, then the 2oz. size is the one to buy. However, if you are doing a full glass job and especially if you are filling in the foreend of a G.I. fiberglass stock, rhen you want the 14 oz. kit. At the difference in price, I recommend you always buy at least a 14 oz. kit. When you have this stuff around, you are going to find all kinds of uses for it and since shelf life of opened containers is so long, it is no problem to keep it around when you close up the containers after use.

OK, so how do you figure out ahead of time just how much Marine Tex you will need to do a job? Well, don't laugh too hard, but I have been known to place a tablespoon or teaspoon around the areas I will bed and add them up as I go around the stock. The total is about what I need and then I add a little extra. It is ALWAYS better to mix too much than too little. In a few rare instances over the years, I was able to mix a partial batch when I did not mix enough the first time and add it before the first batch began hardening. Once or twice, that didn't work out. If you don't mix enough, then the stuff is wasted and you are going to have to spend more time removing or cutting at least some out and then do it again. So even as CHEAP as I am, this is one thing I splurge on. (Oh, that doesn't mean I don't save small jobs or different things to repair when I'm doing full bedding job and use the excess material there.)

Here are some GENERAL amounts I use for different jobs:

A. For a small repair I use:

1 teaspoon and 1 Quarter Teaspoon for resin and 1 Quarter Teaspoon of catalyst.
(Basically the mix ratio is thus 5 Quarter Teaspoons Resin to 1 Quarter Teaspoon catalyst.)

B. For a larger repair or when I bed a trigger housing:

2 teaspoons and 1 Half teaspoon of resin to 1 Half Teaspoon of catalyst.
(Basically the mix ratio is 5 Half Teaspoons resin to 1 Half Teaspoon of catalyst.)

C. For a skim glass job, then I combine each of these above two mixes together.

For a normal Garand or M14 bedding job and when I don't hog out an immense quantity of the stock I use:

D. For a full glass job without a lug, then I use at least this mix:

1 Tablespoon (which is three Teaspoons) and 2 Teaspoons of resin and 1 Teaspoon of Catalyst.
(Basically the ratio here is 5 Teaspoons of resin to 1 Teaspoon of Catalyst.)

E. For a full glass job where I route more out of the stock, I may combine the Mix in "D." with one of the smaller mixes above.

SPECIAL NOTE: When I combine mixes, I ALWAYS get ALL resin of both mixes on the mixing board FIRST, before I add the catalyst. That way it is far less likely to screw up the mix.

F. For a lugged gun and often a double lugged gun, I use:

3 Tablespoons (which is 9 Teaspoons) and 1 Teaspoon of resin and 2 Teaspoons of catalyst.
(Basically the ratio here is 10 Teaspoons of Resin to 2 Teaspoons of Catalyst, which is still a 5 to 1 ratio.

If I don't have a use for the excess bedding material, I scrape it off the mixing board and keep it on scrap of paper or a sheet from a mixing pad. I use that as a gage to tell me when the bedding is thouroughly cured before I break the receiver out of the stock.
 
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