hi, i'm redoing the insid of my 85 mac. the previous owner had small screws holding up the plywood interior paneling to which the cushions were attached via snaps. half of the screws were stripped. i am putting in new panels but am not sure of the best way to attach them to the side walls. also are the sidewalls double hulled and do i have to worry about going througt the hull with the screws? is it better to glue? thanks, stuart
wood paneling
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Hull Liner
Hi Stuart, I've got an '85 M-25. Below the hull/deck joint, I'm pretty sure that is a hull liner. Along the sides above the seating area, it's pretty much right on the outer hull with little (I'd guess less than 1/8" or no space at all) room in between. Are you referring to the factory wood strips which run the length of the deck joint, or did the PO have some paneling we are talking about? I really don't know what options you will have available for attaching other than a high-strength adhesive.
Hi Stuart, I've got an '85 M-25. Below the hull/deck joint, I'm pretty sure that is a hull liner. Along the sides above the seating area, it's pretty much right on the outer hull with little (I'd guess less than 1/8" or no space at all) room in between. Are you referring to the factory wood strips which run the length of the deck joint, or did the PO have some paneling we are talking about? I really don't know what options you will have available for attaching other than a high-strength adhesive.
hull liner
thanks for the reply, i do not know if the plywood that is in back of the cushions is the original or not.they are 1/8" sheets of plywood that go from the deck under the windows tothe top of the fiberglass seat. they were however screwed on by little brass wood screws. they went in to the fiberglass about a quarter of an inch and were not holding well. if i use glue what type of glue would youo reccommend?
thanks for the reply, i do not know if the plywood that is in back of the cushions is the original or not.they are 1/8" sheets of plywood that go from the deck under the windows tothe top of the fiberglass seat. they were however screwed on by little brass wood screws. they went in to the fiberglass about a quarter of an inch and were not holding well. if i use glue what type of glue would youo reccommend?
velcro
They make some strong Velcro these days. That way you could remove the panels if necessary.
They make some strong Velcro these days. That way you could remove the panels if necessary.
Attachment
I have been working on a lot of 26's lately, their construction may be similar. There are 4 main pieces: hull, deck, and two liners, the tub and the overhead (my names for them). There is clearance in some places between the liners and the hull or deck- other places have no clearance at all (like around windows). If you have a 1/4 inch or so, you can install an item called a rivnut. If you design your item to have enough rivnuts installed, it can be securely attached to fiberglass. I have been installing a lot of items with *8 and *10 button head screws into rivnuts. A rivnut tool is available at harbor freight, but the rivnuts are not the best quality. I forgot to say that the rivnuts are a blind fastener, ie: you do not need access to the back of the panel to install them. I have fabricated and installed shelves on the liners and interior dome lights on the overhead with total success. I have a lot of experience with velcro. It's attachment will need an adhesive that is messy, and believe it or not, over time the velcro is stronger than the adhesive. The velcro will eventually pull off leaving a messy area and a failure to support, usually when you most need it. My only application for velcro is sewn to fabric, I am done glueing it on anything. Fiberglass is glass. Screws into fiberglass will loosen over time and crack out. You can start with a small screw and work your way up progressively to bigger screws until you have a hole big enough for a rivnut, which you should have installed in the first place. YMMV
I have been working on a lot of 26's lately, their construction may be similar. There are 4 main pieces: hull, deck, and two liners, the tub and the overhead (my names for them). There is clearance in some places between the liners and the hull or deck- other places have no clearance at all (like around windows). If you have a 1/4 inch or so, you can install an item called a rivnut. If you design your item to have enough rivnuts installed, it can be securely attached to fiberglass. I have been installing a lot of items with *8 and *10 button head screws into rivnuts. A rivnut tool is available at harbor freight, but the rivnuts are not the best quality. I forgot to say that the rivnuts are a blind fastener, ie: you do not need access to the back of the panel to install them. I have fabricated and installed shelves on the liners and interior dome lights on the overhead with total success. I have a lot of experience with velcro. It's attachment will need an adhesive that is messy, and believe it or not, over time the velcro is stronger than the adhesive. The velcro will eventually pull off leaving a messy area and a failure to support, usually when you most need it. My only application for velcro is sewn to fabric, I am done glueing it on anything. Fiberglass is glass. Screws into fiberglass will loosen over time and crack out. You can start with a small screw and work your way up progressively to bigger screws until you have a hole big enough for a rivnut, which you should have installed in the first place. YMMV
rivnuts reply
thank you all for your help. i will look into rivnuts immediatly. what do you think of just using just liquid nails to hold the wood in place? thanks again, stuart
thank you all for your help. i will look into rivnuts immediatly. what do you think of just using just liquid nails to hold the wood in place? thanks again, stuart
Liquid
Liquid nails would surely be easy and semi-permanent. Use a good grade of paneling, because you aren't going to be able to remove it. There is the danger that the next owner will curse you! When installing de-ice boots on aircraft wings, I use a technique wherein you paint a reactivateable glue like 3M 1300 to both surfaces and let it dry. Then you merely wipe the surfaces with something like acetone and press the two parts together. Only one try cause it will bond instantly and will not come apart without destroying something, but you get a great bond. Liquid nails is not as good a bond, but you will have more working time.
Liquid nails would surely be easy and semi-permanent. Use a good grade of paneling, because you aren't going to be able to remove it. There is the danger that the next owner will curse you! When installing de-ice boots on aircraft wings, I use a technique wherein you paint a reactivateable glue like 3M 1300 to both surfaces and let it dry. Then you merely wipe the surfaces with something like acetone and press the two parts together. Only one try cause it will bond instantly and will not come apart without destroying something, but you get a great bond. Liquid nails is not as good a bond, but you will have more working time.
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