Thread: Epoxy Selection

If you're after a bit of fun, ask Mik if using silicone is a good idea :eek:

Richard

Isn't it also a question of why there is that much movement at the starboard end of the transom planks, and not the port end?

If you just seal one end with something flexible like Sikaflex, won't you eventually get movement at the other end also?

So, should you not clean out the seam completely, across its length, and re-seal all of it? Also making sure that here is a good clean bond between the Sikaflex and the timber.

What if the real problem is that the fastenings are loose?

Originally Posted by onthebeachalone

What if the real problem is that the fastenings are loose?

You whack in a 4" nail, liberally douse with petrol, and con your mother in law into taking up smoking in the boat

Yes, first find why you have the problem, then fix it. One must do things in the right order, though it's often less fun that way

Richard

Yeah well! I never found Sikaflex much fun to handle anyway.

Did I hear the word SILICONE?



MIK

The vessel is a traditionally planked cruiser built from Spotted Gum. The horizontal planks are single pieces from bow to stern (40ft long). I can see no indication of glue or corking between the planks of any type. The planks are attached to vertical supports [until I learn the terminology there is going to be lots of this beginner terminology] (roughly 2x2) between 6-12 inches apart which run from deck to keel. The vertical supports then have bow to stern beams (roughly 4x2) on the inside that the I assume keep them inplace.The keel is a single spotted gum beam (roughly 10x10). There are other port to starboard beams both at deck height and in the bilge (10x4) in certain places that I can see that are also sputted gum. The cross beams, from port to starboard, at deck height are probably close to 6x2 or 6x3.

I think the hull is either double planked or strip planked. From the inside the planks are horizontal (bow to stern) and the same on the outside. Double planked? Copper nails attach the planks from the outside.

Other than the ply main deck and ply upper deck the entire vessel is spotted gum. Keep in mind this vessel weighs nearly 20ton. I'd expect the wood to flex.

I have attached a photo of the entire transom area and you can see each of the planking quite clearly through the paint.

I have spoken to a number of shipwrights, in addition to my own research, and they all indicate that the planks move (hence why two pack paints are not suitable). The vessel is in dire need of a paint job, I think it was done in 1996, and the the starboard side transom does not look much different to other parts of the boat, such as the coamings.

The surveyors have said that the gaps in the starboard side transom need to be filled and repainted to stop fresh water from entering. Not that I have asked but none of them have said that the transom needs to be pulled apart.

I understand that movement in planks can indicate underlying problems however there is not much more I can do than have professional boat builders look at it. Should I keep looking around until I find one that tells me it has to be rebuilt?

Now for a positive tact...I understand epoxy is probably not the best choice to fill the gaps as it does not flex with movement? That silicone can't be painted? What's the pros/cons with Sikaflex? Can it be painted? Does it flex with movement? What other alternatives are available?

Hi Darren, I am guessing you would have completed this job already but thought I could offer you information of the product used on our boat to fill exactly the same problems. The shipwrights that performed the work on ours used International Microsmooth http://www.yachtpaint.com/australia/...PageID=13336#1 for all plank joints above the waterline. As the planks above the waterline do not need to expand "as much" as those below, you can get away with using a more solid filler above the waterline. I have attached a pic of them applying this product. You may be able to contact Bote Cote and find out their equivelant product. Sikaflex could also be used in this application, but you won't have a nice smooth sanded finish to paint over. Kind Regards, Pete

Originally Posted by Salted Nuts

Hi Darren, I am guessing you would have completed this job already but thought I could offer you information of the product used on our boat to fill exactly the same problems. The shipwrights that performed the work on ours used International Microsmooth http://www.yachtpaint.com/australia/...PageID=13336#1 for all plank joints above the waterline. As the planks above the waterline do not need to expand "as much" as those below, you can get away with using a more solid filler above the waterline. I have attached a pic of them applying this product. You may be able to contact Bote Cote and find out their equivelant product. Sikaflex could also be used in this application, but you won't have a nice smooth sanded finish to paint over. Kind Regards, Pete

Good on ya Pete! No I have not done the job yet. She has been up on the slip for the last two days being anti fouled and having a diesel servcice. Turned out to be a pain in the butt. The antifoul was done in a day however the diesel service took nearly two days and was done at the last minute. ie 3.30 to 6pm last night. The mechanics ran out of people after they took the job.

I peeled off some paint around a window/portal yesreday whilst I was waiting. We had seen a bit of water beneath the paint so I wanted to see the extent of it. The window is mush for about 4 inches up and down. The window had not been sealed preoprly or has since become broken. We expected as much. Our intent was just to cut out the ply and replace. No can do. The window is set in a wooden sheet about two inches thick and about twenty feet long.

I am intending to dry out the wood and have a look at the area before I make a D on what to do. Anyone had experience with drying rot out and refilling with epxoy?

What's the opinion of the CPES product (http://www.rotdoctor.com/products/cpes.html) sold by the Rot Doctor is the USA? It seems to be utilised for this purpose. I noticed the it's epoxies are carried by solvents. My understanding with solvent based epoxies is the solvent evaporates and leaves gaps in the wood.

Hi Darren

you are right, if you need to thin the poxy then use TPRDA (BoteCote product) or something similar. It thins it out and doesn't leave the voids.

If you haven't already, see Boatmiks website http://www.storerboatplans.com/Faq/faqindex.html

I look forward to the responses etc.

Originally Posted by meerkat

Hi Darren

you are right, if you need to thin the poxy then use TPRDA (BoteCote product) or something similar. It thins it out and doesn't leave the voids.

If you haven't already, see Boatmiks website http://members.ozemail.com.au/~storerm/Faq/faqindex.html

I look forward to the responses etc.

Yes I had seen Boatmik's website. Most informative. If I drilled holes and injected epoxy thinned with TRPDA into the holes will it will leach through the timber or will it harden in the drill hole? I am looking for something that will penetrate throughout the affected area.

The above link is now

http://www.storerboatplans.com/Faq/faqindex.html

G'day Mick,

That is an amazing link. I haven't had time to read all of it yet but I only wish I had found it a couple of years ago. It is like the ultimate "How To" resource and should be recommended/compulsory reading for anybody contemplating working with epoxy - and much more.

Thank you for shareing your considerable knowledge and expertise!

Respectfully

Mick