Home Forums Hunting & Shooting Gunsmithing Cure time for Marine Tex?

I have always allowed at least overnight in a heated furnace room, or 24 hours at room temperature, before shooting the rifle, but read that some wait at least three days.

Wondering what the pros usually do?

Thanks,
Ted

I use gray. Going by memory, IIRC, the ambient temp needs to be warmer than my shop during the winter for a 24 hour full cure. Think you need to have the materials at or above 72 or so degrees, before mixing, during mixing, during application, and during cure time, for it to be machinable at the 24 hour mark. Having a constant temp like a heat lamp, only speeds things up about six or so hours, but having temps dip down into the 60s during the process can double the cure time. So, I make it a habit to wait at least 48 hours for peace of mind. On a big kicker, I've waited 72 hours, for peace of mind. I always mix excess and set aside a lump to test for full cure machinability, also for peace of mind.

Good memory. Just for fun I checked the manufacturer's site. Temperature is a big deal with epoxy, I've had Acraglas Gel act like it would never cure below 60.

marinetex.com

I am no pro, but I always wait 24 hrs just to pop out the action, and another 24 before I shoot it.

I am a pro. I cure at 72 degrees for a full 24 hours. Never had any problem with it being fully cured.

Damn! You actually followed the manufacturer's recommendations??

I have only used the Grey, and have always had very satisfactory results. I mix it in my downstairs workshop where the temperature is usually 55-60F. It always mixes smoothly and evenly, and the working time at that temp seems limitless.

The overnight cures in the furnace room are in 80-85F temp, and the bedding has always been very hard by morning. Have fired the rifle a few times that same day with no apparent problems.

The cures at room temp are done on top of the kitchen cabinets, where the temp can be anywhere from 70-80 degrees.

Appreciate the replies from each of you.
Ted

Interesting to read. I've always waited 24 hours before removing from stock and a week before firing. I leave a 60 watt bulb right above the action on my work bench the first 24 hours. It's usually at least 70, hotter in the summer, and the bulb adds to that. ....sounds like I can start shooting a lot earlier!

Several, years ago, I had a rather unusual situation arise where I had to repair and bed a Husqvarna 9.3X62 with a very badly cracked stock, and be ready for a winter bison hunting trip that I was going on the next day. Long story, won't bore you with the details.

I mixed as usual in the workshop, bedded the rifle and then set it directly on top of the furnace cabinet. The temp on top gets quite warm to touch, but not burning hot.

This all started around 7:30PM. I kept checking the rifle, and about 11:00 it was hard, so popped it out of the stock to check the bedding job. It was near perfect!

Put the barreled action back in the stock, and left it on the furnace until morning. Cleaned it all up, headed out, stopped to sight in on the way, and went hunting.

Never got a bison that day, but the rifle is still going strong, and only needs to be resighted if I change a load. I call it, "The Ugly 9.3", the same bedding job is in there, and it has done its share of hunting and harvest with loads up to 320 gr at near 2200 fps.

Ted

I feel like most resins need quite a bit of heat to really cure properly. A lot of composites that I have worked with cure at 300-400 F. I think that's too hot for Marine tex but I have really good luck with heating it to at least 180 at some point and cure it at 120 most of the time. I the summer here, that just means setting it on a black piece of tin outside. I have done many coupon samples with various heats and the hot ones have faired really well and had a higher hardness.

I also use a heat gun when I mix Devcon or Marine tex to make it soupy so it mixes really well. It thickens as it cools if you need it not to run.

Mix up a whole tube of epoxy in a plastic measuring cup and watch how hot it gets- I have had it completely melt thick measuring cups. Sometimes I need a big batch to fill antlers and such in on knives- have to work fast in volume because it gets VERY hot.

I've worked with some Hexcel ambient cure resin on glass, very much cured in 24 hours, design strength in 3 days, ultimate in about a week heated in the sun to help. Not a lot of difference between design and ultimate. How strong do you really need it?

Yeah, amazingly exothermic. Had to mix in small batches for a reasonable pot life and still had to work fast on hot days.

Hitting the proper ratio was more important for strength, and the resin was quite forgiving in that respect. But still we're not building aircraft here.