Posts
484
Joined
3/19/2009
Location
San Juan Capistrano, CA
US
Edited Date/Time
4/17/2020 9:03am
Hey Guys,
Been working on a project on/off for a few weeks. I took a live edge slab, welded a frame, and made myself a coffee table. Unfortunately, the epoxy didn't cure right and I was left with a tacky mess. So a quart of acetone later, I'm back to finishing the top.
Rather than take the easy route with stain and epoxy, I'm going to inlay carbon fiber into a center strip. It won't run the full length as it shows in the photo - I'll use my router to create a 1/4" inlay with round corners, stopping about 3 inches from each long edge . My plan is to cut the CF and lay it in there.
My concerns are that cutting/fitting the un-wet carbon fiber size is going to be different than when it is wet with epoxy. Is this a valid concern? I'm not looking for perfection, but would prefer to not have it bubble up like carpet.
I don't have a vacuum bagging system and don't plan to take this to that degree. Just looking for pointers and any blind spots before I get started.
Thanks for any help!
Been working on a project on/off for a few weeks. I took a live edge slab, welded a frame, and made myself a coffee table. Unfortunately, the epoxy didn't cure right and I was left with a tacky mess. So a quart of acetone later, I'm back to finishing the top.
Rather than take the easy route with stain and epoxy, I'm going to inlay carbon fiber into a center strip. It won't run the full length as it shows in the photo - I'll use my router to create a 1/4" inlay with round corners, stopping about 3 inches from each long edge . My plan is to cut the CF and lay it in there.
My concerns are that cutting/fitting the un-wet carbon fiber size is going to be different than when it is wet with epoxy. Is this a valid concern? I'm not looking for perfection, but would prefer to not have it bubble up like carpet.
I don't have a vacuum bagging system and don't plan to take this to that degree. Just looking for pointers and any blind spots before I get started.
Thanks for any help!
I'm in the process of making template to guide the router using a mortising bit to form the depression for the inlay. It'll be about 3/16" thick.
My plan is to pour over and wet out the CF on the first go. I'll let that cure, make any needed surface adjustments, then epoxy the entire top as one full surface.
I've done a handful of nice wood working stuff in the past. This one is more about the journey of creating it, challenging myself with some new materials, and just having fun. It won't be a show piece, but will be a little more conversational than a typical wood top.
I'll post pics along the way. I always enjoy feedback and other's perspectives.
Thanks!
The Shop
You're better off buying a piece of already cured pre-preg sheet and inlaying that.
Dragonplate does nice work.
https://dragonplate.com/solid-carbon-fiber-sheets-plates?gclid=Cj0KCQjw…
You can even buy a standard-sized sheet and take it to your local waterjet shop and have it cut to size.
1. Thin layer of epoxy in the inlay recess. Allow it to tack up
2. Lay CF over tacky epoxy. Allow initial epoxy to cure
3. Wet out CF
4. Allow CF/Epoxy to cure
5. Finish entire table top with epoxy
https://youtu.be/ERNt1nGtONI
I have a few more questions for you. Since the bottom of my mold is the bottom of the mortise in the table, I don't really have to worry about how it looks like you would if the first layer was in a mold
I'm going to be cutting the cloth to final size and laying it inside the mortise dry. If I let the base of epoxy tack up, I'm afraid I'll have difficulty getting the cloth to lay exactly where it needs to sit. If I try to move it, I risk pulling fibers from the weave.
I'm thinking it'll be a better idea to wet it out initially, that way I can slide it around and get it to sit just right where it needs to go.
Thoughts?
Another option since you're pretty good with wood would be to cut out a top to hold the carbon down. It could be marker board that you can put a few coats of wax on or you could wrap tyvek tape on so any bleed through epoxy doesn't stick to it. Put a thin coat of epoxy down, carbon, then the board to hold it down. That would make sure it was really flat with no wrinkles or peel up. Actually I like that option better.
Also, before you cut the carbon lay it out on a table and push all the weave together and make sure its lined up. easier to do it now then after its cut. Depending on how much carbon you have and how thick it is you can use spray glue and glue two layers together and that will help keep the ends from fraying and all the fibers lined up. Use really sharp scissors.
I was able to get 2 layers of CF down. It was a lot harder to get things cut and laid down in the negative of the mortise than I thought it was going to be. I have very little experience working with composites, so a lot of this was new to me.
I laid a base of epoxy, waited for that to cure to the point of the slightest bit of tacky, and laid the first layer of CF down. It laid pretty damn smooth and I was able to trim some of the fraid edges pretty well. I wet that out 2 days later, then added the 2nd layer. In hindsight, I probably should have waited for the epoxy of the first layer to tack up to the same point....I ran out of patience I guess.
As the 2nd layer was starting to cure, it was raising up the edges and the some other spots. I had cut and trimmed a piece of 1/4" plywood to serve as a press to get things to flatten out. It's clamped together now - we'll see what things look like tomorrow.
I can already tell that this thing is going to have some character flaws to it. I'm A.O.K. with that. The right way to do this would have been to buy a cured sheet and have it cut on the water jet. But that's just not who I am. I do things by hand with the tools available to me, and sometimes that means they come out rough around the edges. I like it that way.
Thanks for all the help and suggestions. I've learned a ton working on this one. I really hope that plywood doesn't get stuck in the mold.
I have these if anyones interested. Will trade for a bike...
https://www.ebay.com/itm/321702295186
https://www.ebay.com/itm/321702296075
I won't clamp the 3rd layer down. I'll let the thin coat of epoxy tack up, position the CF, then let that cure. I'll top coat it after that and hopefully get a great finish to polish from.
Pit Row
This project has really given me a new appreciation for the prep, effort, and skill involved in working with these materials.
I had an idea that I wanted to bounce off you.
Rather than trying to cut the cloth to size on it's own, I was thinking about cutting a piece slightly oversized. I'd lay it in the mortise when the epoxy is tacked up to the point that it grips but doesn't lock it in. Add that piece of plywood with just some slight clamp force and let it cure.
The next day, I'd use an exacto knife to trim the excess CF cloth material from the mortise, then wet out.
What do you think?
When I cut the first 2 layers to size as cloth, there were a lot of frayed and jagged edges. I'm pretty sure it'd be real tough to get a clean edged look trying to do it like that.
The epoxy/polyester resin isn't wet, but not quite cured either.
Like I said, it's all timing.
The next day, I was able to trim the loose edges with the knife.
It was trying to wet out and set the 2nd layer that I made a mess.
I'm going to try the approach with the next layer that I did with the first. That should give me enough grab on the weave but there won't be resin in the edges.
We're going live with this idea later tonight. I'll keep you guys posted.
Thanks again for the tips and advice.
Things worked out great, aside from staying up until 2am waiting for the epoxy to be just right.
I laid down the weave when it was just tacky enough, put a slight clamp on things, and let it finish curing. I just took a brand new exacto blade and trimmed.
I finally got the CF to lay like I wanted it to.
Now it's time to tape up the edges and pour a shit load of epoxy over this whole thing.
https://youtu.be/M1AM5lIyLwo
I poured about 1.5 quarts of epoxy onto this thing this morning. The backing rod idea did OK - the good news is it held enough material that it had more than just surface thickness.
98% of the table looks great. There are two spots towards the long edge that I should have sealed again. The sanding I did of surface opened up some grain and I ended up with air bubbles. I'll see how bad it is when it cures and decide what to do next.
Overall I'm pretty happy with how things came out and I'm glad I took the time to work on this one.
1 is of my 67 Chevelle SS on the Tail of the Dragon. The other is a shot from riding my 69 Honda CL450 along the Blue Ridge Parkway south of Asheville, NC
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