Finish ? Plus 1 more ?

[Forwardhandle]

I'm currently finishing off 2 glass bows and I'm sanding the limbs & risers to 220 grit and using Duplicate-color clear coat but it got me wondering if there is any finishes that can go over the factory coating on the glass with out sanding it, I have friends that use pre catalyzed magna lac on other types of bows and claim it will stick to almost any surface ?

[Flem]

Maybe with shellac or a vinyl sealer as a bridge coat, but you still have to prep the old surface by cleaning it. Why not sand first for insurance, stripping a finish gone bad really sucks.

[Forwardhandle]

I am sanding & using clear coat I was just curious if there where non sand finishes

[EvilDogBeast]

As an aircraft metal worker and painter, I'll tell you what my trainer told me.  Your paint job is only as good as the surface you put it on.  With that in mind, if there was a no-sand finish I wouldn't trust it.

[4 point]

Definitely take the couple extra minutes to sand it! Even if someone makes a product that can be applied directly, whos to say the fiberglass coating isn't going to let loose from the glass.

[Forwardhandle]

Thanks guys I was just thinking the manufacturer puts the sealed coating on and the wood lams are not this is my first glass bow and I got it shooting perfect where I want Im just nervious about sanding glass...lol Chris your bow looks awesome I was really thinking of a oil type finish in the future like tru-oil but now I know to sand. Like said I was just throwing it out to learn

[EvilDogBeast]

Thanks Ritchie.  Sorry I could have typed that better, came off kind of jerky.  I meant it as a caution more than anything.  When you sand the glass use something like 320-400 and only sand it enough to get rid of the factory glossy spots.  Once all of those are covered in the light scratches from the paper just wipe it down really well with isopropyl or denatured alcohol and double check it to make sure all the smooth areas are gone.  After the light sanding the glass should have a kind of cloudy look to it but you should still be able to see through it if it was clear glass.  I know your bow will look amazing no matter what finish you put on there, can't wait to see some pictures!

[Forwardhandle]

I didnt take it as jerky Chris, I could relate to your aircraft analogy I have owened two small airplanes over the years been a private pilot for 44 years and had one painted so I see your point on prep work , finishes have never been my strong point but its a interesting topic to me !

[monterey]

I agree with the beast on the 320 to 400 for glass.  I know many builders do 220 and it's just fine but 320 is finer {that there is a pun }  My current approach is to sand the entire bow except the glass with progressive grades of paper until the wood is finished to 320 and then do the glass with the 320.  Colored glass looks fine under the auto clear coat and the clear is clear.

[Forwardhandle]

Well on this one it's brown glass I'm going to have to do 220 grit because I ordered a 25 sheet pack from one of the web stores that should get here tonight , but on the other bow maybe I will try lighter grits both are hunting bows so doing the Matt finish , hoping to get one done with the long week end !

[Forwardhandle]

Finaly found a can of this ,the matt is hard to find but was reading the can , it says it takes 7 days to fully cure !

[kennym]

Hey Ritchie, I think that is what I sprayed my bro's bow with, it wasn't a great finish.  It showed white marks with any scuff ,scratch, or bump.

He refinished the bow last winter after one hunting season .....

[Shredd]

Yeah Bro...  I would not just use any finish unless approved by a couple of the boys...  VHT wheel finish has a couple of decent reviews...  Someone did a thread on here about it... (I think Monty)   IMO...  Min-wax Poly in the rattle can does a good job but it yellows... The water base does not yellow but I never used it on bows and don't know how it will go on or hold up...  Don't use Deft...  I don't like the stuff...  Anywhere the string layed against the limbs it left a mark...

    Sand the glass...  Don't worry about changing or ruining your tiller...  You are gonna have to do a lot of sanding to do that especially with 200-300 grit... Glas is some tough stuff...  Follow Monty's instructions...  Wood first, down to 200-300 and then the glass on the flat area...  Save the edges for last and do them very lightly because they can sand fast and change your bow by a pound if you sand and round them too much...

   For future reference...  When joining surfaces or applying finishes almost all surfaces get sanded... In most cases this is more or less called mechanical bonding...  There are exceptions where you don't have to sand... These are called chemical bonds or welds... A good example is gluing together pvc pipe...  Another is spraying on a second coat of auto finish before the first coat fully cures... These are chemical bonds...

   Good Luck Brudder...

[Forwardhandle]

Thanks for the education guys I appreciate it, this is what I have on hand , also the wife has water based polly in her inventory , I have seen Truoil used on other glass threads has any body here used it ? I have used it on many self bows with good luck very durable finish and if you want the matt look pumice powder and olive oil mix works great after its cured ,I also have spray Shellac & other pollys ? , my wife is offering to chalk paint it for me 😳

[Robertfishes]

I always thought the coating on the smooth side of fiberglass was a "release agent" to keep the fiberglass from sticking to the mold when it's made?.  That's why we sand it off before we apply finish. When choosing a finish one important thing is knowing what you are applying the finish over..meaning are you applying finish over a "oily wood" like Bocote or other Rosewoods. Some finishes like  Minwax Spar Urethane do not "cure" over oily woods unless you first seal them with something like a dewaxed Shellac like Bullseye. So back to the original question about sanding the release agent before applying finish..yes, I hand sand it with 320 grit but used to use 220 grit.

[Forwardhandle]

So whats a good recomendation for finish ?? I would like to do it this week end if possible other wise I will hold off tell I figure it out ?

[EvilDogBeast]

I'm not sure about bow glass, but aircraft glass comes out glossy like that as well.  Ours comes out that way because of the heat resistant nylon films used to build the vacuum bag that compresses it.  While it doesn't have any release agent on it, the glossy surface causes paints and other coatings to bead up and run off because it's so smooth.

[jhk1]

I've used Varathane water-based Spar Polyurethane satin spray on a bunch of bows, and have been very pleased with the results. Quickest, easiest way to finish a bow that I've tried. I strongly recommend using only the satin version, not gloss or semi-gloss. It's very fast and easy to use. I apply 5-6 coats, waiting only 5-10 minutes between coats. I typically spray everything but the back glass first-- that way I can put the bow down on the back glass between coats. Before spraying the back glass, I let the last coat on the belly, sides and riser dry for at least an hour. After that, the finish on the belly has dried enough to that you can set the bow down on the belly side of the limbs and then spray the coats on the back glass.

This stuff gives a nice uniform finish. I never sand between coats-- just spray, wait 5-10 minutes, and spray again. When fully dry, the satin finish isn't glass-smooth-- it has a very, very subtle texture. Nothing like an actual textured finish-- it's very subtle. After the final coat, I let the finish cure for at least a day or two. It may not need that long, but I figure if I'm going through the trouble, waiting a day or two before using the bow is no big deal.

It's water-based, so it doesn't give wood that warm amber glow that oil-based poly does. Just yesterday, I sprayed a Hill-style longbow with Eastern Red Cedar limbs and Hickory riser. I wanted to give the cedar and hickory the ambered look, so a few days ago I applied a couple of coats of Minwax oil-based gloss wipe-on polyurethane to the wood surfaces (not on the glass) and let it cure for a couple of days. I then applied 5-6 coats of the Varathane water-based spar satin spray over the entire bow. No sanding of the wipe-on poly or between the spray coats. The bow turned out great.

Here's the stuff. The stuff I got recently has a new label-- it's now got a green label. I buy it at Menards.
https://www.homedepot.com/p/Varathane-11-25-oz-Clear-Satin-Spar-Urethane-Spray-Paint-6-Pack-250281/202057150

[jhk1]

Other posters are right about sanding the glass-- sand with 320 or 400 grit to dull the glossy surface before applying a finish. I really like 3M sandpaper (the purplish or yellow colored stuff you get at Menards or Home Depot; the package has "3X" or "7X" or "10X" on it-- meaning that it lasts that many times longer than cheap stuff). I find that the good 3M 320-grit paper removes stuff faster than cheap 220-grit paper while still leaving a smoother surface. And it does last a lot longer than cheap sandpaper.

[jhk1]

Just a heads-up-- the Varathane water-based spray doesn't go on in fine misty coats. It looks kind of splattery compared to what you may be used to-- not bad, just not super-fine misty look. But don't worry, it looks good when it dries. Don't lay it on thick-- move the spray fairly quickly along so that it doesn't go on too thick. Applying 5-6 coats will cover nicely.