Tru oil and Helmans spar urethane issues

[T Folts]

I put on about 4 coats of tru oil and my fiberglass limbs then sprayed them with the urethane (clear gloss. The results are not what I expected. The finish is rough and textured, is this common? What should I do, I was planning an doing the riser also but not now. I did'nt think there would be a compatibility issue.

[T Folts]

So impatient I decided to sand down the limbs with 320 grit and just go back over with the tru oil. I am a little worried of the outcome if I dont get all the urethane off before putting back on the tru oil. Well see.

[BWD]

I'm a little confused as to why you used tru oil over the fiberglass? I've used a couple of coats on the limbs edges and riser. Then I lightly sanded off what didn't soak in, before spraying with Helmsman spar urethane, but have not used it over fiberglass. Never seen any advantage to using tru oil over glass, when you are going to go over it with something else. When the urethane cures for about three days you can smooth it out a little with fine valve lapping compound. Rub lightly in a circular motion. The further away you are from what you are spraying, the bumper the finish.

[Innocente]

wow i'm glad you posted this.  
i'm almost finished with my first fiberglass build, and i read a tru-oil post that convinced me that it's the ultimate bow finish...your post here just saved me from making the same error.

spose i'll save the tru oil for the wood riser part of this bow, and urethane the fiberglass parts.

[walkabout]

tru-oil is popular for self bow guys, and for some laminate but mostly wood. poly is popular for glass

[T Folts]

I've used tru oil on selfbows with great success and read some old post that said you can used it on fiberglass as well. On the glass its not for protection IMO just a consistent finish. I was getting impatient as to film thickness and decided to get the ball rolling a little faster and hit it with urethane. I think one of two things happened, it was either not warm enough in the basement or I applied to heavy or far away.

[walkabout]

it may just be the mixture of the 2, essentially youre spraying the poly over oil, which is gonna have a big effect. im not farmiliar with using these together but when painting other stuff if your material is dirty/ oily from touching it you get orangepeel. this can happen if its cold too. id try a scrap piece then see if it turns out the same. maybe the orangepeel is the result people want to cut the shine of the tru oil.

[BWD]

Many bows, including glass bows, are finished with tru oil. It's long suit is ease of application and the ability to repair or touch up scratches, etc. by adding another coat. However, it is not a real tuff finish, and imo  offers no advantage when used over glass when poly or urethane is to be applied over the tru oil.

[T Folts]

My next on will have t-bird I hope.

[Art B]

That spar urethane will do just as you described over raw urethane. But I've never seen it do that over Tru-oil. Did that happen with the first coat over the Tru-oil? Or did you happen to apply a second coat later than 3 hrs and less than 72hrs?

ART