Jimmy hard top hatch repair

[Sandtrap9072]

So, i am going to attempt to try and fix the crack in the rear hatch of my jimmy. This is my first fiberglass job and may have some questions along the way. Have any of you repaired a cracked hatch like mine? What i am thinking about doing to repair the crack, i will reinforce the inside of the hatch with some fiberglass mat (seems like i can reach it) and then coat the outside of the hatch where the crack is with some fiberglass filler. After that i will sand it down and re-gel coat with a roller to get the texture. Is there anything i should do to prep the crack before i apply the resin? Any input would be greatly appreciated.

[A1971Blazer]

I'm working on mine now too....one thing I discovered while researching is that you must use epoxy resin rather than polyester resin. The material used for the original top and hatch is SMC (sheet molded composite) not fiberglass. The polyester resin will bond but won't stay bonded to it. I got my epoxy resin from this company.
http://www.fibreglast.com/product/Sy...0/Epoxy_Resins

[notsolo]

I used some stainless sheet metal, for reinforcement, polyurethane caulk, to glue to inside of hinge plate area, pop rivets, to hold in place until caulk dried. J-B weld to fill voids and strengthen the top edge. Make sure the hinges work well, this was why mine failed in this area. Also cleaned and lubed sliders.

[pound41]

There are several good threads on this. Most impressive to me A member showed how to split the hatch in 2 pieces make his repairs from the inside and put it back together

[Sandtrap9072]

Originally Posted by A1971Blazer

I'm working on mine now too....one thing I discovered while researching is that you must use epoxy resin rather than polyester resin. The material used for the original top and hatch is SMC (sheet molded composite) not fiberglass. The polyester resin will bond but won't stay bonded to it. I got my epoxy resin from this company.
http://www.fibreglast.com/product/Sy...0/Epoxy_Resins

What are you using as far as the fiber glass itself?

[A1971Blazer]

I have some laminated fiberglass sheet material that I sometimes use in my shop for customer jobs.

https://www.mcmaster.com/#grade-g-10-garolite/=15c4hnu

Also you have to use fiberglass cloth rather than mat...the mat is only activated if you use polyester resin...

I'm also using some stainless sheet metal to beef up the mounting and latch areas...
after much research..I found that using 3M Scotch-Weld EC2216 is the best bonding glue.
I experimented with it on the hatch to metal bond....I could not break it apart....

I'm a few weeks away from doing the final repair but I will post some pics when I get it going...

[Livrat]

I will chime in here, I agree the hatch is SMC, but SMC is mostly misunderstood, It is actually just fiberglass that is pressed into a mold that uses a release agent mixed in the resin in able to release it from the molds, you can use either fiberglass cloth or mat but It is a MUST to use either epoxy resin or a specially formulated SMC polyester resin, If a "standard" fiberglass polyester resin is used it will "sort of" adhere and look okay but it will eventually fail.
I might be the member who Pound41 mentioned about splitting a hatch in two and doing repairs on the inside, I will say it does take great amount of time, It took about 40 hours of labor to split, repair and glue back together!

[A1971Blazer]

From the Fibre Glast application information:

Note: All Fiberglass Mat is made to be used with resin to create hard, composite parts. However, it is NOT compatible with epoxy resin. Mat has a light binder that holds it together. During lay-up, it requires styrene to break down that binder and allow for complete resin saturation. Epoxy does not contain styrene and therefore cannot be effectively used with the mat. Use polyester or vinyl ester resin with these applications.

[Livrat]

Ok, thanks! I learned something new, I was told by an old body guy that mat was acceptable with epoxy, Its a good thing I used cloth!!

[Sandtrap9072]

i may have gotten extremely lucky and scored a mint hard top for 100 bucks. The hatch has no cracks in it. Plan on going to pick up the complete top this weekend. Depending on the condition of the new hatch will dictate if i will move forward with the fiberglass job. by the time i would have bought all the supplies to do this, i prob would have been close to the 100bucks i am paying for the top.

[A1971Blazer]

Originally Posted by Livrat

Ok, thanks! I learned something new, I was told by an old body guy that mat was acceptable with epoxy, Its a good thing I used cloth!!

I tried to cover every base before I got started on my repair....I talked extensively with the technicians at FibreGlast regarding the repair of the SMC..they also have a great deal of information on their web site....

I've also studied your repair of splitting the hatch apart....even back when these were made, they had some strong azz glue...your write up made me decide to just open up the weak sections and re-enforce them the best I can and live with it. Mine is fairly good except for the left side latch area was broken completely out.




this is the cracked section that I cut out


I'm fabricating a stainless bulkhead to go inside....around the curved area and across to the side and bottom....

[Sandtrap9072]

So I have the new hatch apart. This hatch does have a crack by the handle. My question is how would one go fixing this? Can I put a v in it and put some fiberglass filler in it?

[A1971Blazer]

Originally Posted by Sandtrap9072

So I have the new hatch apart. This hatch does have a crack by the handle. My question is how would one go fixing this? Can I put a v in it and put some fiberglass filler in it?

filling it will only be a temporary fix....there won't be anything to strengthen the cracked area....if it was me I would try to re-enforce it somehow on the inside....try to get as large a piece of thin sheet metal that you can work in there and epoxy it in place...then "v" it and fill...

[GMC-YA68]

I accidentally pulled mine in the garage with it in the "UP" position.

Used some West Systems 404 filler adhesive in the cracks. One layer of carbon fiber on each side and then E-glass cloth with epoxy. Looks fine and won't break again. Did nothing but grind the cracks down and push it back into place.

[Sandtrap9072]

http://www.eastwood.com/contour-ligh...filler-3l.html

i am wondering how this would would hold up.