HELP! with bad scarfs

So I used a jig to cut my side rails to scarf. After gluing they turned out OK. Then last night I glued my scarfed 1/4" hydrotek. Just took off the boards that were clamped on and im not to happy with the results. There is a bit of a gap at the ends of each piece, just does not look good.

 

SO: How can I save my 150 dollars worth of ply wood? I am thinking about adding thickened epoxy to where the gap is to make it smooth out, then sand it down a bit to make it smoother (or possibly just leave it a little thick there?). Ill be glassing over the outside so I would think a little bump will smooth out after layers of glass and epoxy. BUT I thought I read something on here that said to never sand joints cause you will loose strength. So if I cant sand then how can I fix my mistake?

AND: What can I do so I dont have this problem when I glue my other side and the bottom?

Views: 126

▶ Reply to This

Replies to This Discussion

Permalink Reply by Kevin C. on March 3, 2011 at 5:50pm
Ben ,don't worry too much about this...it's your first build and these things happen,do you think picasso's first painting was perfect?Do what you said and fill the gap with thickened with wood flour and after it has cured take a heat gun to it and scrape off the excess .Be sure not to use too much heat and follow the grain ,don'tscrape across the joint perpendicular.Sanding will take away wood before it removes the epoxy so be careful with a random orbital when you clean it up.For the next one ,dry fit the 2 pieces and mark with a pencil or sharpie on the edges(where you can see the cross section of the plys) so you have a reference when you glue them up and lay them together.Be sure to clamp the two separate sheets to your table so they won't move and then put your weight on the joint.
Permalink Reply by lhedrick on March 3, 2011 at 6:47pm

 

 

When you say there is a gap, I assume you mean where the thin edge of one sheet ends.  If  that's all it is don't worry about it.  Slide a knife blade under it to get an idea of how far back the gap goes.  You can mix up some epoxy and work it under the edge to fill it.  The epoxy will be active for 24 hours.  In colder conditions as long as a few days so you have a window in time to fill the gap and have it all bond together.

 

When it's all cured use a scraper to remove excess epoxy to get it flat.  It just needs to be flat enough for the fiberglass to flow over smoothly without lifting up and pulling air under the glass.  Glass needs to flow over objects smoothly.  If you were to try to fiber glass over a gap or other edges it will lift up.  Like laying a credit card on the panel and trying to glass over it.  At the edge of the card the fiberglass will lift up.  The edge needs to be filled.  So, when you scarf is down it just needs to be relatively smooth.  If the edge of one sheet did not bond flat, don't sand it of.  Feather the high spot with thickened epoxy.  If you do get a bubble, slice it open and work epoxy under it.  Then cover with plastic and put a weight on it to press it down and get it bonded.

 

If you mixed the epoxy properly things should work out fine.  If you are going to paint the boat only you will know about it.  If you were going to varnish just go ahead and do it.  I have a feeling it's not as bad as you are indicating.

 

If you can, post an image so we can get a better idea of what happened.

 

One piece of advice I can offer with regard to building is to try to go slow and enjoy the process.  I often get in the mode of trying to pick up the pace to get things done.  When the boat is done I miss the process and always want to sell my last boat so I can get back in the shop and build the next one.  Take your time and give it your best to enjoy the process.  While it great to complete a boat and get on the river, there is also a let down because you don't have anything to do.

 

 

Permalink Reply by Robb Grubb on March 4, 2011 at 12:23pm
Eh'men brother...
Permalink Reply by Ben Kittell on March 3, 2011 at 6:57pm

I know I like things to be perfect, tying flies drives me nuts cause I look so close at each little detail but when I do that to flies that I have purchesed I often find that they are less perfect then I think. As everyone says its a learning prosess and I am greatly enjoying it. I should have a pic taking divice soon so I can start adding pictures to all these questions im asking.

 

Thank you all again. This is such a great website and the people make all the differance. Every time I think I have destroyed my boat I get many answers to any question I ask, along with support that gets me back in the garage to continue to have fun and learn tons! 

Permalink Reply by Dave Z on March 5, 2011 at 5:34am

Im late on this, but I'll echo the rest.

 

1. don't worry about it

2. use more filler next time. avoid a "starved" joint. 

3. go ahead and mix up some thickened stuff and fill it, press wax paper over it and drive out the bubbles

4. as said, use a SCRAPER, do not sand.  In fact, if you don't have any scrapers, go buy a set of cheap BAHCO ones form woodcrafters supply.  Use one on glue joints, the other on wood.

 

 

RSS

© 2024   Created by Randy Dersham.   Powered by

Badges  |  Report an Issue  |  Terms of Service