Rough Surface Finish- What can I do better?

I thought I did everything right.   I sanded 220, did two alcohol wipe downs, brushed epoxy on then rolled it out, and immediately tipped it out.

What can I do better to not have that rough surface?

Please see picture:

https://picasaweb.google.com/114717787929554738224/BuildingWoodenBoatCLCNortheasterDory?authkey=Gv1sRgCKCBzczm_aKs2wE#5978049826023335234

 

Also see this picture comparing where I use plastic sheeting in the bottom of the picture and didnt use plastic in the top area of the picture:

https://picasaweb.google.com/114717787929554738224/BuildingWoodenBoatCLCNortheasterDory?authkey=Gv1sRgCKCBzczm_aKs2wE#5978048739531319506

 

Any help appreciated as I have a lot of epoxy to put on the inside of the boat today!!

 

Curt  830/997-8120


7 replies:

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RE: Rough Surface Finish- What can I do better?

Curt, that looks normal to me, especially for a first coat on bare wood. Epoxy doesn't level out as well as paint or varnish does, so it needs some scraping and/or sanding to get a smooth surface before painting.

Old Yeller

RE: Rough Surface Finish- What can I do better?

Old Yeller,

OK, thanks...I am hoping to put two coats epoxy on the entire inside of the boat today (obviously without sanding/scraping between), except the bottom and panel 1, they already have 3 coats, then a third and final coat in the morning, then sand that one...sound right?

RE: Rough Surface Finish- What can I do better?

  I didn't bother to sand anything until after the first coat of epoxy had sealed the wood. It doesn't matter how smooth your first coat of epoxy is, what's important is how smooth the last coat is. Just knock off the little nibs and sand or preferable scrape off the drips and runs as best you can and put a second coat on. Remember that your smooth final finish comes from sanding and that you don't want to sand wood, just epoxy. If you are finishing bright, you have to build up and sand down enough layers of epoxy and varnish to fill all the low spots and remove the high spots. If you paint you can fill with a fairing mix of epoxy and microspheres or balloons and then sand level before priming. 

  You wind up sanding a lot of the epoxy off in the process of smoothing the surface unless you use a fairing compound to coat the whole boat and then you just sand that smooth instead. You also sand off most of the primer and some of the top coats too. I am using a Harbor Freight 5" R/O palm sander and with 120 it makes short work of any flat areas leaving the corners to hand sanding with wood blocks modified to match the angle of my laps. Once I switch to varnish and paint/primer I will go to 150 and save the 220 for the topcoat. Don't be afraid of using an aggressive grit, you have to be careful at first, but it quickly dulls a bit and is very controllable by hand or by machine. 

  Be sure to wear a face mask with appropriate canister and wear gloves, the dust is just as dangerous as the wet epoxy as far as allergic reactions.

RE: Rough Surface Finish- What can I do better?

Thanks for the info!  

My situation is that I am under a time crunch so anything I can do to make the steps go fast is great.  I'll knock down the "nibs" on the areas I epoxied last night and proceed to do a coat on the entire inside.

I have never used microballoons...it sounds like using that savies time?

Also, yes I have the latest Dewalt ROS low profile unit and an auto switch to turn on the shop vac in the other room when I turn the sander on, and wear long sleeve shirts, a tuk, and my trusty 3M respirator with NIOSH 6001 filters...I assume those are the right respirator filters?

 

 

Thanks!!

RE: Rough Surface Finish- What can I do better?

To save time, apply your epoxy coats wet-on-wet, without sanding between. You can shave off any runs and drips with a scraper between coats, without waiting for the epoxy to cure hard enough to sand.

If you are going to use paint rather than varnish, you might also save a bit of time by filling the weave of your fiberglass using a slurry of epoxy and microballoons, rather than a series of unthickened fill coats. But I would still finish with a coat of unthickened epoxy after the microballoons have been sanded, and then carefully sand that.

Old Yeller 

RE: Rough Surface Finish- What can I do better?

  Micro balloons sand very easily, far faster than wood flour. The drier you mix it the faster it sands down, but the less resin the weaker the result. It is purely nonstructural and is used just to fill the low spots without adding weight. I get small amounts from TAP Plastic, but it is widely available.

RE: Rough Surface Finish- What can I do better?

Thanks guys for the great information!   I'm an epoxy fool this afternoon and appreciate your help, thanks for taking the time to offer the info, very helpful.

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