Notching A/C Box

[Babaganoosh]

I'm going to need to notch my A/C box on the firewall, will this affect performance of the A/C? I need a 1.75 tube to pass through the side.

I plan on doing it with fiberglass, will this be a issue?

 

[Babaganoosh]

TTT anyone have any suggestions?

 

[SouthernYank]

As long as you make sure not to hit the evaporator, and rebuilding the area with fiberglass is what we always did.

It won't affect the performance.

 

[Babaganoosh]

I talked to my local mad scientist that I trust his opinion on and he said the same. Now to learn how to use fiber glass.

Looks like I have tons of room to do my slight modification.

 

[SouthernYank]

I don't remember the exact ratio for mixing the resin with the MEKP (hardner), but should be on the container. You don't want to much hardner or it will kick off too fast for you to work with and it can also start a fire. But don't put too little or you'll be waiting forever for it to cure.

You should start with prepping your box, cutting out where you need clearance then grinding out an inch or so on all sides. You want to take the material around the opening where you measure your inch on all sides down some so when you layer your matting it ends up flush and not a hump.

Cut your pieces of matting to cover opening, you'll want to soak them with the resin (mixed with the MEKP of course) with a paintbrush on a piece of cardboard or something you don't mind getting ruined. Paint some resin on the area you are patching then start applying your patches. You will need a roller to make sure you get all the air out from under the glass or it will end up a void. You should get the hang of it fairly quick.

 

[Babaganoosh]

Sounds like a plan thanks for the tips

 

[SouthernYank]

No problem, if you have any questions just let me know. Here are some from where we had to fix my dads kayak due to the patio heater getting too close. You can see where we ground down to allow the fiberglass to build up without looking jacked up. Also we made a mold from the other kayak to pop on, needless to say the nose is bulletproof on it now.

 

[Babaganoosh]

Very nice, Biggest issue I see as of right now is figuring out what to put on the back side to create the shape I want then being able to pull it off.

 

[SouthernYank]

So you're just passing some DOM through it? take a papertowel roll or something of the like and put some painters tape on it then put some glass on it for your shape, the painters tape should keep it from sticking too bad and you could always sand the tape off.

Notch the area out, lay your piece in and glass it to the evap housing.

 

[Babaganoosh]

Will the cardboard stick to the other side or will it be easily removable? Sorry never worked with glass before.

 

[SouthernYank]

If you put the painters tape on the cardboard roll like you see on the nose of the kayak the cardboard shouldn't stick as long as there's no holes in the tape. Now some of the tape will stick to the fiberglass but you can easily grind that off if it won't peel off.

 

[Babaganoosh]

Ok, I see what you mean now. I had to look back at the pictures and re read what you said.

 

[SouthernYank]

 

[rampage]

Or you could put a thin layer of Vaseline on the tape as a mold release. Or better yet, a piece plastic wrap over the cardboard tube with Vaseline on the plastic.

 

[ryoken]

make sure you have an appropriate grind taper to the surrounding area, AND THAT IT IS VERY ROUGH....

the heater isn't technically fiberglass, being dissimilar materials, proper adhesion is key...


and just remember polyester based products wait for no one! working speed is key.. make sure you have EVERYTHING set up prior.. brushes, precut glass, etc...

for best strength it's best to alternate layers between cloth and mat...

 

[skunked]

you can use the blue foam at home depot to make a form as well. IIRC they use a wax over the foam so the fiberglass releases from the mold.

 

[ryoken]

wax or PVA are the standard release agents.. I prefer PVA for most odd jobs... wax is great for production molds, etc..

even if any of these don't release, foam, cardboard, etc, it's generally no huge tragedy... as mentioned earlier just hit with some sandpaper, grinder, etc and it knocks it right off.. in the case of cardboard, just saturate it with water and scrape it out...

you generally need/want to sand/grind/it somewhat smooth after anyways.. you have to if you want a nice finish.. and you at least want the fresh resin to not be shiny for even just a rattlecan douching...

#1 bodywork lesson, shiny = bad...

 

[SouthernYank]

Even though it wasn't my dept. I still picked up a few things from the glassers at Hatteras.

BTW, your project is on a smaller scale but when sanding this you will hate life laying in bed at night. It's worse than residential fiberglass insulation imo.

 

[ryoken]

you worked for Hatteras.. cool.... I've worked on 100's over the yr's.. shot plenty of Imron on them!

 

[SouthernYank]

Yeah I used to work on the 60c, loved it there. By far the best job ever until the economy took a dump then they consolidated our Swansboro NC plant with the New Bern NC plant and I couldn't afford the commute at the time so decided to start working overseas. Would leave this money for that job in a sec.