Sunday, November 22, 2009

Pourable Transom Repair the longer story....

March 5, 2007
Bill Brenemen

High Springs Florida 32655

Pourable Transom Repair

First of all, let me say that I am not any kind of boat mechanic, restorer, refurbisher, or whatever. I am a pretty good mech on old JohnRude's but that is about it, - and an all around 'Handyguy'. The Seacast material is well known in MFG circles, as the way to replace these dual skin radius transoms. I had used some leftover Seacast for a project, and was not confident that it was something that I could do (especially by myself). When I stumbled across the Nida-Core and talked to those people a few times, I realized this was the product for my boat and my skill level. I am not familiar with other boats and construction, so you will have to make your own decision as to this working for you. Up front you need to know that you are going to be pouring a liquid with the consistency of 50W oil in the void you are creating. If it has a place to run out, - it will. On the other hand, after the prep work, the job took less than an hour to complete.

I recommend that you go to the SeaCast site especially the forums section, and the Nida-Core site. Jim Coffman has a 'how-to' article on the MFG Boats pages that depicts the process perfectly. Lay the transom out on grid paper or mark it out on the transom itself with a dry erase marker. I like the paper as it gives me something to 'noodle' on. I came up with a total of 1640 cubic inches. the Nida-Core pours 1255 per five gallon bucket, so ordered two buckets figuring on having 2 1/2 gallons remaining unmixed. This was $295.00 including shipping. I had to order the MEKP from another source for $26.00 total, but only used half of it. I now have 10 ounces of high explosive in my shop to dispose of{Transom opened to core} All of my pics of the core removal are archived on the MFG site. I robbed this one from Jim's article, (I hope he doesn't mind). I removed the aluminum extrusion from the top and used a skill saw to make a plunge cut on the inside of the inner and outer skins and just moved it back and forth until I had the fiberglass cap cut off the top.



Then it was a matter of drilling, chipping and vacuuming to get all the wood core removed. I wanted to preserve my thru-hull fittings so this made it a little more difficult for me. If you do not have these types of fittings, or know how to replace them, then you could just get 'down and dirty' with a chain saw and remove the core in hours. I found that by drilling the center section of laminate, I could then pry other pieces out in larger sections.







The upper corner blocks on the MFG just 'sit' on the top of the transom core. I think they are just there to attach the deck to at the rear. I replaced these with marine plywood, and cut them four inches longer so that they would be well down into the resin. This allowed me to pour without building 'dams' or removing the deck.









Here we have the core completely cleaned out, and all holes in the inner and outer skin patched from the inside.











I glued a few spaces in place to keep my transom thickness so that my extrusion would fit back properly.











The inner skin felt kind of thin, so I tensioned with a 'Deadman' to keep it form bowing.











I sat the trailer on stands (I could envision one of my "maypop" tires going flat) and leveled it from side to side and as much as possible from front to back. This created a situation that I did not think of, which I will go into later..











I draped the whole work area and put down drop cloths, got out the jeans, long sleeved shirt, gloves and mask and goggles. I usually take material data sheets and warnings with a grain of salt, but this stuff sounded pretty scary, as far as fumes and skin contact.









This is the unstirred, unmixed product, I wanted to show the consistency here. I stirred both buckets with the clean mixer blade and then poured 21/2 gallons into a separate bucket to mix. I have to say this product mixed and stirred easier than latex house paint. I poured the first two mixes, poured off 1/2 of the second bucket , mixed, believing I would have a gallon or so left.











-- WRONG! I was an inch short of the transom top! I did not want to try to recalculate mix ratio's at this point, so I went ahead and mixed up the remaining 21/2 gallons. I poured to the top, filled up some molds I had laid out for 'experimenting', and placed the remaining product in a cooler with ice packs to 'hold'. This was per Gary's suggestion.

This is the poured product. It gelled up within minutes and generated so much heat across the transom, I had to leave it until the next day. It was at this stage that I realized what had happened to the extra product. My calculations weren't off, I forgot {did not think about it) that some material was going to run between the hull and floor between the stringers. I could feel the heat about six inches forward on the bottom, but only about one inch on the sides. I just totally lucked out here. I got a better job than I had planned by accident. I guess one thing you could do in prep, is to pour water into the void a gallon at a time, to see what happens. Then just wet vac back out and let dry. My cooler did not work at all, I think this material hardened up just as fast as the rest. (Maybe not enough ice)

The next day it took a couple of hours to replace the extrusion, scrub the transom down with comet, and apply a few coats of Poly-Glow. I would like to paint the sides and transom one day, but first I want to get it all back together and go ride! This product allowed me to do a job that would have been impossible (for me) using any other method. You could honestly do this in a weekend, if you had every thing in place and an action plan. Guestimated weight of new transom core 57 pounds.

Friday, November 20, 2009