Project: How to Fiberglass a Boler

How to Fiberglass a Boler:

What? I know – it’s a odd topic found here on, but it has a purpose.

Most of you know Bryce and I fix up old Boler trailers and send them off into the world with happy new owners. Thus far we’ve done 4 and we’ve kept Tipsy, which makes 5. On Instagram we’ve been asked more than a handful of times about fiberglass. So, this post is for those who are looking for a bit of direction.

Know that we’re total DIYers – our own brand of expert. We are knowledgeable and you can see some of our results below.

How to Fiberglass a Boler

I’ll share some tips and then also one of the most helpful videos ever for learning how to fiberglass.

Prep Tips

You’ll want to sand down all the fiberglass, yet on the area you’re going to repair, you’ll need to do a bit more sanding – ensure you sand down the gel coat fully around a large hole if you’re going to completely fill it in. Also, make sure you wear a mask – the fiberglass and resin can be quite harmful if inhaled.

How to Fiberglass a Boler:

Large Void Tips

Okay, the video I’ll share below goes over quite a bit of detail, yet it’s mainly for fiberglassing over something specific – not covering negative space. So, I want to talk a bit about that.

We covered about 9 fully void holes on Tipsy.

First, we lined a piece of wood with parchment paper. Then, from the back side of the void we screwed it in place. Fiberglass won’t stick to the parchment paper and you need something strong, like wood (not cardboard) which will give you resistance when applying your first coat.

Then, once you have 2 or 3 layers (however many you think you need) – we did 3 and sanded down quite a bit – you’ll remove the wood, screws, and parchment paper.

Yes – you will have small screw holes – you can follow the tips below for those.

How to Fiberglass a Boler:

How to Fiberglass a Boler:

Small Imperfection Tips

On small holes, cracks, or large chips (too big for Bondo) we use fiberglass to do the repair. One big tip is to do all of your fiberglass work at one time, since it can be messy. So, identify all of your imperfections and spots that you want to repair. Then, cut out all the different shapes you’ll need. I prep them and Bryce does the application.

Work quickly since it will harden fast, depending on your resin to hardener ratio (another reason to do all the work at the same time – do the math only once!).

For these small imperfections you’ll most likely only need one layer of fiberglass and then you can sand down to make it smooth. The more accurate you are with cutting your shapes, the less sanding you’ll have to do (and the less fiberglass you’ll waste).

How to Fiberglass a Boler:

How to Fiberglass a Boler:

Finishing Tips

Since we were covering up a massive hole we had some small imperfections in the larger sections. As such, we used this fiberglass filler.

You’ll sand the finished fiberglass work, then fill, sand, then fill a bit more, and sand again.

One trick we learned – don’t eyeball it. Close your eyes and feel with your hand. You can feel the imperfections much easier than you can see them. Also, don’t underestimate those tiny issues – they will magnify when you paint.

How to Fiberglass a Boler:

Here the large back window is completed – fiberglassed, sanded, filled, and feels smooth.

How to Fiberglass a Boler:

Below you can see the finished product painted – looks so good!

Guess how many holes are actually on this side of the trailer? There are 3 – yes, we covered 3 completely void holes on this side alone. Cool, eh?

How to Fiberglass a Boler:

Tackling the fiberglass work yourself can seem like a daunting task – take it from us, you can do it! Get the right tools, the right products, and the right direction and you’ll be all set.

Here’s the Fiberglassing Video Tutorial I love!

Thanks so much for visiting and reading. I hope this helps give even just one person the confidence to tackle fiberglassing themselves. Happy repairing!


  • San Fran

    Just a quick question, did you thin out your resin like the video?
    Thanks so much for you article, has given me the confidence to do this myself!!

    • Ali


      We add the hardner to the resin, so it sets, but I’m not sure what you mean by thinning it out – we don’t dilute it with anything.

      Hope that helps!

      • San Fran

        In the video he thins it out with some alcohol! Apparently spreads easier.

        I didn’t do it though.
        What a messy experience working with resin!

  • Rita Hagman

    Hi I have a 1975 Boler white on top and yellow below. It needs a new paint job on it. What is the best kind of paint to use? Do I have to sand it all first? Or maybe I should just wash ane wax it?? My daughter thinks I should keep it it’s original yellow but I love the Turquoise color! Should I keep it yellow or go Turquoise? Thanks Rita

    • Ali

      Hi Rita!

      What awesome colours! We did Sunny D and Benny in white and yellow – so fun! Yes, if you’re looking to re-paint, then you’ll need to sand, fill any imperfections (since paint will highlight them), and sand again in progressively higher grits. We’ve used the roll and tip method with marine grade enamel, and have also sprayed it, too – spraying is a more professional look. We’ve also used high quality automotive paint and sprayed it, which is a top-notch look. We did Scooby Doo and Toots in the Bali Hai colour, which is turquoise and we loved it just as much as the yellow. You pick the colour that works for you, both will look beautiful!

      Thanks for reaching out and have fun with your project!

  • Deliris

    Hi! I just bought one that needs a lot of work. I am in Victoria BC, are you close (for visual and advice or for hire)?

    • Ali


      Thanks so awesome – congrats on your new-to-you Boler! We’re in Northern Alberta, so not that close at all. We’ve shared a lot of tutorials on our Instagram page (@tipsy.the.boler) which might help. Happy renovating.

  • Velma Young

    Thank you so much for this information. I own a 73 13ft boler, and will be working on it this spring with my brother’s help.
    Any other info would be greatly appreciated.

    Thank you

    • Ali

      Hi Velma,

      Do you have Instagram? We post all of our tips, tricks and video tutorials on there. Feel free to check us out @tipsy.the.boler

      Happy renovating!

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