Does anyone have any negative experiences using epoxy in the repair of wooden car parts? I hear the positives and I have been in touch with the folks at Abatron to request info but what's the downside?

Dave

Oh wow. I just used the Abatron products for a window sill repair, and was thinking I whould write up my experience. For what it’s worth, here goes.

The project was a house window sill set on a stone sill (yeah, I know this isn’t railway preservation, but I don’t get much chance to do much of that). The sill was softwood, but judging from the amount of weather it has taken over the last fifty years, it must be Douglas Fir. Having an eaves trough that periodically overflowed above it kept it moist, and my dad didn’t help the situation when he caulked around the outside of the triple track storm window frame; all the water that came through the screen during the summer was trapped by the caulk. Not only was a fist sized portion of the sill missing, but the window jamb was punky at the bottom, so just replacing the sill was not an option. The problem was very similar to a wood window sill on a coach or streetcar, where water had continually leaked in behind the sash.

I ordered up a wood repair kit from Abatron, consisting of the LiquidWood® wood consolidant, WoodEpox® adhesive wood-replacement paste, and solvent for clean up. Mindful that the resin wouldn’t penetrate into wood if it was wet, I closed the storm window and left the inner sash open to the house for a couple of weeks to dry the area out.

I started by removing the storm window frame to expose the sill and the wood / stone interface. After removing all the loose remains of the rotted wood, I found I had about a 3 X 3 inch triangle that was totally missing from the sill, and a hole the size of a silver dollar missing from the bottom of the brick mould. The adjacent wood was punky, but what the heck, that’s what wood consolidant is for, right? I liberally brushed on the liquid resin until the wood could absorb no more, then mixed up a baseball sized gob of putty and filled the voids, sculpting it to shape. Then I left it to cure for a week.

It rained that week, and when I returned to the project the next weekend, I was not pleased. The “consolidated” wood had warped and pulled way from the putty. The putty, however, was solid as a rock, and I was able to dig more of the punky wood out from behind it without disturbing it. What I found is that the consolidant, un-thinned, only penetrated 1/8” or less, making a rather thin flexible shell, which moved when the wood behind it swelled from the rain and separated from the solid putty. Interesting ly, I was able to excavate an inch wide band all around the solid putty, back to wood that was in decent condition. I then dosed that with liquid resin, and mixed more putty to fill the gap. The following week everything had set up hard, and sanded out to an invisible patch. I was even quite successful at sculpting the ogee shape of the brick mould in putty.

What I learned is that if punky wood is constrained so that it can’t move, the liquid resin will do a good job of sealing it. The bottom of the jamb, which I didn’t attempt to excavate at all, looks fine. However, the solid portion is likely only 1/8” thick.

The WoodPox putty is not very easy to work with; it continually pulled away from the work when trying to knife it, and I finally learned a technique of “patting” it to shape. It also doesn’t seem to be any harder or stronger than regular old polyester automotive body putty. However, it has the advantage of being totally compatible and intermixable with the liquid resin, which ensures that the putty develops a water tight bond with the ragged end of the remaining wood, and it is worth using for this reason alone.

One problem I can foresee with car restoration work is that if the putty ends up merging together two or three separate structural members of a wood carbody, it will likely crack as the car weaves down the track. I contemplated a similar situation in my house repair; I really didn’t want to bond the epoxy repair to the stone sill, as when things move with the change of seasons, I want the epoxy to stay with the wood, not the stone. I ran a layer of masking tape between the epoxy and stone to try to establish a shear plane, but I don’t know how successful I was, as the liquid resin creeps EVERYWHERE. I think in the future I would use wax paper, or possibly vinyl sheet (Visquine). At any rate, after the patch was sanded and painted, I caulked the interface with the stone for a permanent seal, should the patch actually cleave where I want it to. As to the connection of the sill, jamb, and trim, these are now unified into one piece. Luckily, these wouldn’t be expected to move much relative to each other in a building; this may be more problematic in a railroad car.

In all, it appears to be a useful tool; another one to keep in the ol’ bag of tricks, but it certainly won’t work miracles. I’ve heard of repeated applications of the resin, thinned with solvent, being used to successfully consolidate the rotten mortise and tendon joints of coach sash, and indeed, since no one solid part of the joint is thicker than ¼”, the material does seem to have the ability to seep along the crack between the tendon and mortise and fully saturate the wood. But I suspect trying this same technique on thicker stock, such as a door, will leave a hollow center between two thin skins of epoxy / wood matrix. From my limited experience, it would appear that it is better to excavate back to solid wood and replace what is taken out with epoxy putty.

Dennis,
I just went through the same repair on my 1923 home. The bottom of a sash in one corner was dry rotted and part of the jamb was bad as well. I didn't like the way the epoxy was soaking into the bad wood so I removed everything back to good sound wood. Then I coated the wood with the epoxy and then used the paste to build up the profile. I think the paste needs the resin for adhesion, I can't see this stuff hanging on to anything without it.

I am not certain that the Abatron is all that they say it is. The wood consolidate is just slow drying epoxy resin and over priced. Using fiberglass resin should do the same thing. Autobody filler will do the same thing cosmetically however it is not structural as the Abatron claims to be. Acetone will clean up better then the furnished solvent and it isn't as smelly.

Cosmetic repairs can be done with a good grade of autobody filler. There is a correct way to use this so that the chance of failure would be less.

There is a product called "Durhams Water Putty" or some such. It is a powder in a 1 lb round can. The thing I liked best is you can mix it as thin or as thick as needed. I have used this product in repairing rental properties. As with the other products you have to get back to the fairly stable wood. You also must be careful not to join the repair with brick, stone or outside veneer.
What I found really helpful is the product will dry as fast or slow as you need (more water or less water) and is very paint friendly.
I tried not to use Epoxy products. Mainly due to the fumes. My repair business was houses and business properties where there were always people. I have used the "Bondo" auto products on pot-metal pressure regulators with great success.

Dear Dave:
The downside is that ABATRON is difficult to use as described below.
Save yourself all the grief and use "WESTSYSTEMS". It is vastly superior to other products made for the same purpose. Check out their website.
J.David
P.S. I have no stock in Westsystems, just a very satisfied customer.

I would suggest looking back in the archive, a few months ago there was a discussion about a museum, which was doing a in service style restoration and was going to be stored inside, where they used a wood consolidator and putty. The car in the topic was a red wood sheathed boxcar, not sure if it was a double sheathe or single.

Rich C.

We've used a number of different products. Surface prep is the ONLY problem when it's all said and done. Like Dennis said, the hardener only goes in a short distance. Any chance that moisture can get behind the replacement material will result in frequent repairs. A good oil based primer to SOAK the wood does seem to give a good base. If you're doing nail holes prime and then a light sanding to smooth and a filler. We've used the MinWax two part filler and and just plain Bondo and both work in different locations. Make sure after they're sanded smooth that multiple cover coats of a sealer (paint,varnish, etc) are applied and kept in good shape. Remember, Pullman is supposed to have had somewhere around 15 coats to seal the wooden cars when they were built, sanding between coats.
Herb Sakalaucks
Colfax Railroad Museum

We have used both West System and Arbatron epoxy systems on our wooden cars at Ardenwood. The both work well. Both have a learning curve. We have also tried some of the polyester fillers (auto body filler, and similar putties.) These materials have become a significant tool in our restoration arsenal (but are not a miracle cure by themselves)

We have used the products in several ways, to impregnate and rebuild car frames, including sills, to repair weathered siding (a failure) to rebuild moldings and other contoured wooden shapes, and as a rot preventative.

We try to prevent locking joints. In some cases we have used plastic wrap or other film as a barrier in mortis and tennons. Other times we have disassembled the object and treated the individual pieces. The wooden boat guys tell us if you make the structure rigid it will fail.

We have bedded splices in epoxy.

All the epoxies are toxic to the fungus which causes wood rot, so we have been sealing checks, cracks and holes in car sills.

As noted above we tried to first treat weathered car siding with various liquid epoxies (Get Rot and Arbatron) then rebuilding the eroded edge with epoxy or polyester fillers. We have found this will eventually crack and fail. In the future we will reside the car.

We have had good success rebuilding interior molding and detail where cut or broken, by building up the profile, mostly with polyester filler. We have found it reasonably easy to stain it to match nearby wood, and have even drawn or painted on appropriate wood grain.

Generally, all of these materials and techniques result in a more brittle part. We have had our best success on cars that see limited operation, with the exception of the use to seal beams and sills to prevent rot in the first place. It a car is expected to be operated regularly, we are more likely to replace the wood in kind.

A big thanks to all who have responded. Maybe you would be interested in the nature of the project. The car in question is a 15ft 3in electrified horse car (Baltimore City Passenger Railway #417 - build approx. 1887) at the Baltimore Streetcar Museum. I have been working on this project for some years. We have recently discovered some minor rot in one of the car end sills and the decay of some of the interior panel work which is attached at this point. None of these locations are visible to the casual observer since they are covered with the seat when in service. We have used Bondo products as well as other fillers in the past, but have never tried epoxys. We have a rather large platform project in the works on one of our Brownell single truckers, and I want to be armed with the knowledge of the best materials and methods available. I will try to get some photos available in the near future. Once again, many thanks.

Dave.

Sounds like what you need first is a rot killer, something that you can dose the affected area with, that will soak in and make the remaining wood toxic to the rot organisms, before you patch. What is everyone using these days, now that Penta is gone?

I note with interest that Abatron sells “Bora-Care” a boride solution for treating decks and teimbers in ground contact situations. Whoops, they used to sell it, but I can no longer find it on their web site.

From what I’ve read on borides, the biggest problem is that they are water soluble, and will eventually leach out. Randy mentioned they use the liquid epoxy as a wood sealer. Would treatment with Bora-Care, followed by a drying period to allow the water to come out of the wood, followed by sealing and repair with epoxy sound like a reasonable protocol? Penta had the advantage that the carrier solvent was a rapid drying hydrocarbon, but we can’t use that anymore. However, the water based boride solution should work, just take longer to dry. The epoxy would then seal additional water out, while keeping the boride compound in the wood, where it will continue to protect the non-deteriorated wood.

Comments anyone?

I've been away from this business for a few years, so I don't know the brands any more. Sodium borates are used as wood preservatives and flame retardents. They are water soluble, also they are hygroscopic. That means that you have to get the treated wood pretty warm to get the last of the water out so that the thinned epoxy will wet the wood fibers. To retain the effectiveness, the treated area needs to kept dry. A good coat of paint, without holidays, works well.

Copper napthanate products are pretty good wood preservatives. They are green and turn grey to nearly black on exposure to air. Heavily pigmented oil base paints will eventially cover treated areas.

I would sure do some tests on wood scraps to make certain there are no compatibility problems.

Termites don't like either of these products.

Max

If it was mentioned above, I missed it somehow.
I did not see any mention of a product called Git Rot.
I have used it for years on non structural parts of wood boats. By drilling small holes into the affected wooden parts, then injecting the Git Rot mixture into these holes, it does soak fairly thoroughly throughout the rotted wood. The wood turns very hard and much stronger than the soft, flaking stuff it was before the treatment. It won't varnish well after that, but it will take paint. It can be sanded, ground, drilled and screwed into.
The wood, in my experience, does not change shape in any way.
For whatever it's worth.
Mark D.

Here is a web site with some general information about epoxy repairs: http://www.epoxyproducts.com/rot.html

I've used both Abatron and West Systems. They both seem to be great products and selecting which one to use on wood coach work for me depends on application. The Abatron system's liquid wood absorbs into dry wood much more effectively (and deeply) than the West System but conversely the West System creates a stronger filler than Wood Epox

Disclaimer: I've never used their products but found the information to be of interest in better understanding some of the marketing hype.

--Richard

We have used get rot in the past, but prefer the Arbatron system for consolidating punky wood. The Arbatron system allows you to thin it out with acetone to allow it to penetrate the rotten wood better.

Get Rot has the advantage of being locally available… (as does West System) which can be a real advantage in a volunteer organization where you suddenly realize its Friday and tomorrow is a work day….

To bring the whole conversation to a conclusion, in our case, epoxy is generally used to preserve old material, in museum sense. In most cases we would be better off replacing the material, if we were an operating railroad, responsible to shareholders. The exception in our case is sealing beams.

You had better read about thinning epoxies. Acetone will weaken the product even though it thinned the product as you wanted. There are thinners specifically for the different epoxy systems and it is better that these are used.