Davis Instruments790 FSR Fiberglass Stain Remover (16-Ounce)

I use this on my boat to get rid of the dark stain from the water line. It takes it right off with very little effort. It also worked great on our shower floor.

I recently noticed brown stain lines running down the front end cap of my Rv. The unit is parked under an oak tree with new leaves coming forth. The "Tanin" from the sprouting leaves has caused the streaks. I have tried EVERTHING to remove the stains on my $35,000 Rv with NO results.This product kicked Azz and was so easy to use. Washes off with water, and is AWESOME!! ALL STAINS GONE!! WOOHOO

I've been meaning to write a review on FSR for a long time. I used it once 10 years ago with zero success. I would have given it zero stars. Then I tried it 6 months ago and fell in love. I don't know if the formula changed over the years but what definitely changed was my approach to using it. Instead of slopping it on and hoping for a miracle the first round I decided to apply multiple applications over several days.Here is what I've found. If it's a serious rust stain you're not likely not going to get back to pure gel coat with FSR alone. However, you can get close. Just slopping it on and walking away won't always do it. Try agitating the area with FSR on a q-tip, sponge or rag. Let it sit for 10-15 minutes then come back and re-apply. Wait. Reapply. Repeat. I basically did this to two dozen small rust spots on the topside of my boat over a period of a week. It would only take me 5 minutes to reapply and I just kept doing it until, believe it or not, the spots disappeared.In addition, the bottom had a ton of stains from leaving the boat in the water for a several days without bottom paint. I thought they were there forever until I saw how successful FSR was on the topside. I took a foam paint brush and just slathered it on a 2 foot by 2 foot spot on the bottom of my boat. This faded MUCH faster than the rust spots and in most places only required 2 coats of FSR. For the bottom I would rinse the treated spot with water between applications and this seemed to work great. For the topside I tested both leaving the FSR on and reapplying and removing the FSR first with water and reapplying. I did not find that one way or the other accelerated the process.All said, I am now a big fan of FSR. You just need some patience and persistence to get it work to its full potential.

this stuff is like a jelly that works like a charm. I had no issues removing the who knows how old yellow stain on this 1979 boat. I learned that a little goes a long way and the best way to apply is to use one rag to apply a layer over an area and use another rag or a drill brush to rub it in. I only used the drill brush on rough areas. works extremely well, and if another product is worth more or less I would still buy and recomend this stuff.

It promised the world and I had hope. Said it would remove the toughest stains on fiberglass. We have a pool where the paver sealant leaked and we can't get the stain off. This stuff actually made the area look worse...even after multiple tries. Avoid

It is no different than any other product that I have used. I still can’t remove the brown stain that is on the bottom of my fiberglass shower.

Great product. I’ve used it for years! Be patient and let it work for a couple minutes ( don’t let it dry out) and you’ll be happy with results. I’ve removed red wine stains!

Never disappoints.

FSR works great to remove water line & stains on fiberglass boats

I got this to day and as you can see the diffrent between two products. Orginal must be blue but this two is not!!

It works awesome on cleaning the front of my fifth wheel and the bugs don't stick to it after .

Removed hull staining completely with virtually no effort - highly recommended

Very good product but arrived damaged