The C-Brats Forum Index
HomeForumsMy TopicsCalendarEvent SignupsMemberlistOur C-DorysThe Brat MapPhotos

Tips, Tools and Tricks for undercutting balsa core

 
Post new topic   Reply to topic    The C-Brats Forum Index -> Hull, Deck and Fittings
View previous topic :: View next topic  
Author Message
wexcellent



Joined: 28 Sep 2023
Posts: 12
City/Region: Portland
State or Province: OR
C-Dory Year: 2002
C-Dory Model: 22 Cruiser
Vessel Name: Spicy G
Photos: Spicy G
PostPosted: Fri Jan 10, 2025 2:55 pm    Post subject: Tips, Tools and Tricks for undercutting balsa core Reply with quote

As I scour threads dealing with cleaning wet/rotten core materials through existing holes I see references to routing, using a dremel, etc. but haven't encountered much yet in terms of specifics. I have routers, dremmels, roto zips, etc and I am curious what bits, hand tools and practices people have used to best effect.

With larger holes like the hatches or the gas fill caps I am not so concerned, more the undercutting 1/4" or 1/2" holes in the fiberglass. I have only just started on repairs but already see the need to fabricate some kind of 90 degree hand scraper.

Thanks!

_________________
2002 Cruiser 22' - "Spicy G"
Back to top
View user's profile Send private message
clayhubler



Joined: 03 Aug 2019
Posts: 342
City/Region: La Center
State or Province: WA
C-Dory Year: 2003
C-Dory Model: 22 Cruiser
Vessel Name: Hammerhead
Photos: Hammerhead
PostPosted: Fri Jan 10, 2025 3:49 pm    Post subject: Reply with quote

For small holes I found the best was to use an allen wrench in a drill. Usually I would cut the short end of the allen wrench a little shorter and then stick it in the hole. This worked pretty well. For the larger areas like lazarette hatches I made a little tool out of 1/4" aluminum:


_________________
Clay on Hammerhead
Back to top
View user's profile Send private message Send e-mail
thataway



Joined: 02 Nov 2003
Posts: 21207
City/Region: Pensacola
State or Province: FL
C-Dory Year: 2007
C-Dory Model: 25 Cruiser
Vessel Name: thataway
Photos: Thataway
PostPosted: Fri Jan 10, 2025 4:29 pm    Post subject: Reply with quote

I use a Dremel tool, with 1/4" bit head, Often the flexible shaft is a better tool. There are also flexible shafts for the Roto Zip 1/4" shaft tools. and high power vacuum.

For separating foam from hull or balsa, the Fein MultiMaster or copy bay almost every tool company-I have corded by Dremel, and battery powered. The scraping tool, or about 1 1/4 to 1 1/2' wide fine toothed cutting blade--just don't cut thru the bottom of the boat!

_________________
Bob Austin
Thataway
Thataway (Ex Seaweed) 2007 25 C Dory May 2018 to Oct. 2021
Thisaway 2006 22' CDory November 2011 to May 2018
Caracal 18 140 Suzuki 2007 to present
Thataway TomCat 255 150 Suzukis June 2006 thru August 2011
C Pelican; 1992, 22 Cruiser, 2002 thru 2006
Frequent Sea; 2003 C D 25, 2007 thru 2009
KA6PKB
Home port: Pensacola FL
Back to top
View user's profile Send private message Send e-mail
wexcellent



Joined: 28 Sep 2023
Posts: 12
City/Region: Portland
State or Province: OR
C-Dory Year: 2002
C-Dory Model: 22 Cruiser
Vessel Name: Spicy G
Photos: Spicy G
PostPosted: Fri Jan 10, 2025 10:07 pm    Post subject: Reply with quote

Thanks guys.

Bob, I am really hoping it doesn't come to breaking out the Fein, finger's crossed. I've never done fiberglass repair and would rather not start, though doing it under the gas tank probably wouldn't be a bad place for my first time since no one will ever see it.

Clay I will definitely be experimenting with the allen wrench idea, I have a whole coffee can of extras to work with. I like the tool you made, I have made similar for a couple of other applications and don't like using them unless absolutely necessary because they can do a lot of damage to materials, clothes and flesh if you aren't really paying attention. I need to look and see what kind of slot cutting router bits I have and maybe pick up a couple more because they should be perfect for the larger openings. Having one with a top mounted bearing and one with a bottom mounted bearing I should be able to quickly and safely prep the openings.[/img]
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic    The C-Brats Forum Index -> Hull, Deck and Fittings All times are GMT - 5 Hours
Page 1 of 1

 
     Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You cannot download files in this forum



Page generation time: 0.074s (PHP: 37% - SQL: 63%) - SQL queries: 21 - GZIP disabled - Debug on