Can you just drill into fibreglass?

[returnofthemac]

I have a 26M and have a few mods in mind for the exterior and interior. I have never worked with fibreglass before and there are mixed results online.

Can you treat fibreglass like wood and only use screws to secure something like a bimini? Or do you have to drill all the way through and use a nut and bolt?

I believe that the M doesn't have a wood core, but I would still to use butyl tape to prevent leaks.

In the interior, can you get away with just using screws? Are there special screws for fibreglass?

[kmclemore]

The answer is 'it depends'.

On the thicker fiberglass bits, you can drill into it and use stainless sheet metal screws to secure things. HOWEVER - if it's going to be something that has a fair bit of vibration or leverage against the 'glass, then I'd use a bolt, washers and nut to secure things (so... yeah, most of the time you're using a nut, bolt and washer(s))

On thinner fiberglass, you must use bolts/machine screws and I'd suggest penny (fender) washers to support the material and prevent it from cracking.

If you're mounting something that will be subject to vibration (as almost everything on a boat is!), then I'd use Rawl Nuts (aka Wellnuts) to mount your item. They have a rubber surround that cushions the vibration and prevents cracking of the fiberglass over time. These may be used on any part of the boat (interior/exterior), and work well for 'blind' areas where you can't access the back to install a washer and nut.

Some advice:

- Apply masking tape to the surface first to prevent chipping of the gel coat when drilling or cutting fiberglass
- Go slow, and use a sharp drill - 'brad point' bits that have side flutes work best to prevent chipping of the 'glass (ones like these: https://www.amazon.com/DEWALT-DW1720-Br ... B005GOM3VO
- Protect yourself from loose fiber dust - it itches like a bear if you don't, and it's toxic to breathe

• Wear an N95 type dust mask
• Cover exposed skin with long sleeves and gloves
• Wear safety glasses / goggles
• Coat skin with talcum powder to prevent skin irritation (it clogs your pores so that 'glass fibers don't get into them)
• Take a COLD shower afterwards. (Taking a warm shower opens the pores and lets the fibers in!)
• Wash fiberglass dust-exposed clothing separately, and use a fabric softener to ensure fibers are washed away

[Brian]

You need the Bimini attachment cars from Blue Water Yachts.

https://shop.bwyachts.com/product-p/2801-1v0.htm

No holes to drill and you can adjust the location fore and aft.

[returnofthemac]

You need the Bimini attachment cars from Blue Water Yachts.

https://shop.bwyachts.com/product-p/2801-1v0.htm

No holes to drill and you can adjust the location fore and aft.

Thank you both, your expertise is appreciated!

Brian, for the bimini this is exactly what I have been looking for! I couldn't find anything online but I assumed this is a generic part that I could pick up at West Marine? Or are those tracks unique to MacGregor?

It's very helpful to know what can and can't be done with fiberglass.

[Jimmyt]

You need the Bimini attachment cars from Blue Water Yachts.

https://shop.bwyachts.com/product-p/2801-1v0.htm

No holes to drill and you can adjust the location fore and aft.

Thank you both, your expertise is appreciated!

Brian, for the bimini this is exactly what I have been looking for! I couldn't find anything online but I assumed this is a generic part that I could pick up at West Marine? Or are those tracks unique to MacGregor?

It's very helpful to know what can and can't be done with fiberglass.

If you don't buy from BWYachts, make sure you measure your track so you can buy the right size. The tracks come in different sizes, and West Marine won't have a Mac expert to help you.

[kmclemore]

....Or are those tracks unique to MacGregor?

The tracks are not unique, but I'd buy from Blue Water Yachts for two reasons - first, they offer decent prices and are great folks to work with... and second, we MUST continue to support our ONLY real source for MacGregor/Tattoo parts at every chance we get, since without them the Mac/Tats would be MUCH harder to maintain.

I buy everything I can from them. For example, I recently needed to rebuild the braking system on my original Mac trailer... I could have bought generic stuff from any trailer dealer, and maybe even found it a wee bit cheaper if I really dug around, but I bought it from BWY because I wanted to support them, I know I'm going to get a good product that fits, and if I have a problem I know they'll stand behind their sales.

[OverEasy]

Ditto!

BWY has competitive prices, great availability and excellent support.

While West Marine has ‘a name’ they most often just leave you to your own devices.
WM general only have clerks with little to no experience in the store or on line (there are always exceptions) who don’t know or care about what you’re looking for, why you’re doing it, options to get it done or how things actually work on boats in general or MacGregors in particular whereas BWY has long term experience, working knowledge, are resourceful and considerate to a fault.

From my very first call to my most recent BWY has consistently provided excellent prices and service.

Best Regards
Over Easy

[returnofthemac]

Yeah, I can appreciate supporting a small business over a large corporation. It's more important these days than ever.

[ART005]

When I drill through fiberglass, I try to use one bit bigger, tape off bottom of hole, fill with slow set 2 part epoxy mixed very well outside the tube. Then after suggested hardening time, redrill the hole. I use a small pilot hole to hit the middle and then the proper size (slightly smaller than 1st bit).
The idea is that slow set epoxy will seep into the exposed drill edge and protect against water seepage.