which weld on should i use?

[blackthunda77]

i have the option of getting #3 or #4 locally. which is better for me. im making a coast to coast internal overflow. which is best to use when i have to fill some pretty small gaps, lets say 1/16-1/8th MAX. here are some pics.

some dry fitting
http://img36.imageshack.us/img36/3048/1242784644299.jpg (http://img36.imageshack.us/my.php?image=1242784644299.jpg)

http://img36.imageshack.us/img36/1475/1242785476221.jpg (http://img36.imageshack.us/my.php?image=1242785476221.jpg)

[troylee]

neither will work for filling any gaps or voids....the only difference in them is the drying time.....use 16 for your project.....it would be your best bet imo.

[blackthunda77]

dang it! not what i wanted to hear. well he asked me which one i needed and i said 3 or 4 and the guy said he had them so maybe he has 16 also i just didnt ask. hope so.

[TAB]

I beleave 4 is also notflamable, but it might be the other way around. The average DIYer will not see a diffrence. Depending the gaps, you might be able to remachine the edges and remove them.

[troylee]

im pretty sure if this is a store or company you are talking about and it has 3 and 4 they will have 16 also.......its pretty common....

[mixer911]

16 is a gel and fills small gaps, 3 is fast Setting, 4 is moderately fast-setting time (up to a couple mins)

[bradbmbj]

I have heard of adding some acrylic shavings to 3 or 4 to thicken it some, but I have not tried it and do not know of the strength rating after you do this, maybe troylee can give some advice.

[mixer911]

<a href=showthread.php?s=&postid=15047151#post15047151 target=_blank>Originally posted</a> by bradbmbj
I have heard of adding some acrylic shavings to 3 or 4 to thicken it some, but I have not tried it and do not know of the strength rating after you do this, maybe troylee can give some advice.

I have done that also and it works, but is a little messy and not as clean as the 16. You also want to use #4 for that, #3 would get hard before you have the shavings all dissolved. Also want to use very fine shavings. I used the powder from the table saw after ripping the acrylic.

[blackthunda77]

no worries, i got 16. was expecting it to be more like caulk but its more like syrup. i gotta find some applicator tips to make it a more clean application next time. no worries though, its just an overflow and ill be painting it black with krylon fusion as soon as a flush trim it tomorrow after work. here are some pics.

http://img32.imageshack.us/img32/9383/1242868808704.jpg (http://img32.imageshack.us/my.php?image=1242868808704.jpg)

http://img32.imageshack.us/img32/4058/1242869664787.jpg (http://img32.imageshack.us/my.php?image=1242869664787.jpg)

http://img39.imageshack.us/img39/1742/1242870763730.jpg (http://img39.imageshack.us/my.php?image=1242870763730.jpg)

for size comparison
http://img39.imageshack.us/img39/6379/1242876417193.jpg (http://img39.imageshack.us/my.php?image=1242876417193.jpg)

[blackthunda77]

excuse the crapy job on the overflow teeth. it was my first attempt, i guess the bit was really used and was getting choked while i was making the cuts, on top of that i had to do it free hand :(

[BeanAnimal]

Not to rain on the parade here...

16 does not do a good job for mechanical joints. 3 or 4 should be used. You should machine the parts to get rid of the gaps. If you can't, then 16 can be used to fill in the gaps. 16 still has a decent amount of volitiles in it and therefore shrinks severely. Use many thin coats to fill a gap, not big globs (they will skin over and leave huge bubbles and weak spots).

[troylee]

16 will be fine i promise.....its not pretty due to the fact it does shrink back about 30percent and leave bubbles as bean stated but the overall strength will be fine for a overflow.....a 100gal display, not really safe, but you are in the clear no worries.....:)

[mixer911]

If your looking for a "caulk like" Acrylic glue then you would want 40. It is is a kit and would be mixed like resin. It is thick like caulk and can be applied with a syringe (no Needle). It is good for sealing bigger gaps..... The whole idea is to not have those gaps though :D ..... Nice clean flush cuts

[BeanAnimal]

Agreed.... 16 will likely be strong enough for the overflow in question. On the other hand, I see a lot of people using 16 (or reccomending it) when 3 or 4 should be used.

[TAB]

I avoid using 16 like the pleague... I honestly can't think of a reason I would use 16 on any project, big or small.

Granted, I have tools at my disposal that most DIYers could only dream about.

[blackthunda77]

came out fine. i by no means am ready to start making acrylic tanks professionally but i used 4 to glue all the joints, waiting for that to dry, then i used a bead of 16 to fill in some gaps. leak tested it this morning, and i would give it a 95% had on small drip coming from a corner. gave it a dab of 16, tested it and vioala, no leaks. im pretty happy with it being my first acrylic diy. now i just have to flush trim it and ill be painting it black and ill be good to go. im sure that if i was able to get better cut i wouldnt even have had to use the 16, but i can only make due with what i got, and with what i got i feel like it came out great, esp for what im going to be using it for.

[BeanAnimal]

:)

[BeanAnimal]

TAB,

I pretty much agree. 16 does not create a strong joint and it looks like hell no matter how careful you are... I actually tossed the pint can I had in the garbage.

[blackthunda77]

ok so then how should i get better joints so that i do not have to use 16? i have access to a table saw. i used the blade that was on there which obviously was for wood and was old and had about 40-50 teeth im guessing. i even bought a 200 tooth blade for myself but returned it since i couldnt get the old blade off. then i have access to a router and table but the router is a ryobi so its not the best and the table is kinda skimpy. shouldd i str8 cut the pieces and then routh all the edges like a 16th of an inch? or should i say, WTH and just have the plastics shop i just found cut me the pieces to size and i can just finish them with some sandpaper and assemble.

[troylee]

im with ya bean on the 16......i truly hate the stuff but it does work and its gets the job done.....and it is readily availiable for applications and people like him who dont have all the tools and accsess to the most recommended procedures.....i replaced my 16 with 40 years ago, but that glue is not really for everyone and in alot of cases its hard to get just a pint locally i get it by the case...........now to your question thunda....blades for a table saw i recommend a triple chip non ferous blade 80tooth will do ya fine......there pretty expensive thou for a single project......router bits get a nice triple flute 1/2" shank flush cut bit and do just like you said rough cut your pieces a 1/16th over size and route them flush for a nice smooth flat edge.....btw. you can loose the router table if you like and feel it is to much of a hassle, just remove the router and if you have a base simply attach it and use a long straight edge stuck to your piece with double sided tape and let the bearing on the bit ride down your straight edge...hth.:)

[blackthunda77]

"triple chip non ferous blade 80tooth" and "triple flute 1/2" shank flush cut bit" now is that what im asking for when i go to HD or Lowes or wherever? does it say all that stuff on the boxes?you guys have some links online i can look at visually to see what your talking about? thanks.

and as for the price.....yea, some of the stuff like blades and bits r way to expensive for me right now since i live in a condo and dont have the tools, so it doesnt make sense to buy a $30 router bit and a $50 saw blade for a $20 overflow. but rest assured, my fiance promised me that once we get a house with a garage she'll buy me all the table saws, router, sanders, chop saws i want. just dont have the room to put all that stuff at right now.

[troylee]

yes sir, just tell them a triple flute, flush cut. router bit.........the non ferrous blade is used for cutting aluminum and such but from exp. i like the way they cut acrylic and other plastics......they sell a blade just for plastics but i like the ones mentioned above more......oh ya the 1/2" shank is just the diam. of the router bit make sure your router accepts a 1/2" shank, some smaller trim routers and such only take a 1/4" shank, not sure which router you got???? if you have 2 collets which are the parts that hold the bits which some routers like the porter cable come with both sizes go for the 1/2" shank they have less vibration which equals a smoother and less chatter finish.....

[Donw]

Use #3 for cast #4 for extruded and 16 as an interior bead like kalk to fix or fill poor machining. The #3 or #4 holds the project together the 16 just fills the remaining gaps. The bigger the bit the smoother the surface. 1/2 spriral end mill make a great finish.

Don

[blackthunda77]

ok well then its obvious that abig part of my problem was the tools (bits). what do you guys reccommend to use to make the teeth in the baffels, and in my case the front of the overflow. i had to do it freehand on the router table but as i was doing it the bit would melt some of the shavings and it would seize the bit and thats where most of my chips or ugly cuts happened. also whats the best way to do it, just plunge it in slowly at once or push in then pull it out a bit and bring it back in as to take of only small amouts at a time?

[troylee]

<a href=showthread.php?s=&postid=15051545#post15051545 target=_blank>Originally posted</a> by Donw
Use #3 for cast #4 for extruded and 16 as an interior bead like kalk to fix or fill poor machining. The #3 or #4 holds the project together the 16 just fills the remaining gaps. The bigger the bit the smoother the surface. 1/2 spriral end mill make a great finish.

Don
i agree with this besides the first 7 words!!!!!!!why would you recommend a slower solvent on a material that breaks down faster????do you have a reason behind this or exp.????im really curious behind your reccomendations here.......i would go the opposite route if any thing i actually just use 3 and 40/42...hmm:smokin:

[troylee]

i personnaly just cut all my teeth on a table saw more teeth and smaller lines looks better imo. and a less chances of a snail or critter getting in there...here is a pic of one kinda hard to see it but you will get the idea...:)
http://i127.photobucket.com/albums/p160/aliyasue/work/IMG00135.jpg

[Donw]

<a href=showthread.php?s=&postid=15051596#post15051596 target=_blank>Originally posted</a> by troylee
i agree with this besides the first 7 words!!!!!!!why would you recommend a slower solvent on a material that breaks down faster????do you have a reason behind this or exp.????im really curious behind your reccomendations here.......i would go the opposite route if any thing i actually just use 3 and 40/42...hmm:smokin:

#4 doesnt craze the cheap acrylic like #3. #5 is even better but almost impossible to find at a local type supplier.
The thick versions are also hard to get at local suppliers and why I didnt mention either.

Don

[blackthunda77]

<a href=showthread.php?s=&postid=15051654#post15051654 target=_blank>Originally posted</a> by troylee
i personnaly just cut all my teeth on a table saw more teeth and smaller lines looks better imo. and a less chances of a snail or critter getting in there...here is a pic of one kinda hard to see it but you will get the idea...:)
http://i127.photobucket.com/albums/p160/aliyasue/work/IMG00135.jpg

shoot...that is alot cleaner looking. ohh well. next time ill try doing it with the table saw. looks good!

[troylee]

<a href=showthread.php?s=&postid=15051769#post15051769 target=_blank>Originally posted</a> by Donw
#4 doesnt craze the cheap acrylic like #3. #5 is even better but almost impossible to find at a local type supplier.
The thick versions are also hard to get at local suppliers and why I didnt mention either.

Don
makes sense....but i have never had a problem really with extruded crazing unless it has been heat formed then i have seen numerous problems..........

[TAB]

FWIW... if its extruded stock, I don't even send it thru the router table. a properly set up table saw with the correct blade makes cuts clean enough to use 3/4 There will be some small bubbles.



I use a dove tail jig and a router to cut my teeth.( the cheaper models don't really work for this) In the past I used a table saw with a miter t and peg.

[blackthunda77]

<a href=showthread.php?s=&postid=15054393#post15054393 target=_blank>Originally posted</a> by TAB
FWIW... if its extruded stock, I don't even send it thru the router table. a properly set up table saw with the correct blade makes cuts clean enough to use 3/4 There will be some small bubbles.



I use a dove tail jig and a router to cut my teeth.( the cheaper models don't really work for this) In the past I used a table saw with a miter t and peg.

you ll have to explain this dove tail jig stuff to me. got a link so i can see one? and you totally lost me on the miter t and peg. you gotta remember im new to this stuff.

[blackthunda77]

ok here are the final pics. i leak tested it this morning, had a very small drip in one if the corners. dabbed some weldon 16 and i was good to go. after work i brought it to my friends house and flush trimmed the box. then i drilled the bulkhead holes, brought it home and gave it a few coats of krylon fusion.

http://img34.imageshack.us/img34/3848/1242907788585.jpg (http://img34.imageshack.us/my.php?image=1242907788585.jpg)

http://img34.imageshack.us/img34/4398/1242960025173.jpg (http://img34.imageshack.us/my.php?image=1242960025173.jpg)

http://img33.imageshack.us/img33/6870/1242960057438.jpg (http://img33.imageshack.us/my.php?image=1242960057438.jpg)

also if you guys are interested, i will start to post in my build thread here on in. heres the link if you wish to follow and continue to offer advice. thanks so far for the help.

http://reefcentral.com/forums/showthread.php?s=&threadid=1640789